ecocompatible, biodegradable polymers. plastic items...

UNIVERSITY OF PISA

Ph.D. in CHEMICAL SCIENCES - XXII Cycle

Ecocompatible, Biodegradable Polymers.

Plastic Items

Preparation & Characterization

Arianna Barghini

Supervisor: Prof./Dr. Emo Chiellini

Tutor: Dr. Elizabeth Grillo Fernandes

Department of Chemistry and Industrial Chemistry

SSD: CHIM/05

ACKNOWLEDGEMENTS

During the work on this Thesis, my life was characterized by some events

that modified it.

My marriage, the born of a child and the discover of a thyroid carcinoma

weren’t loss many time to imagine the moment in which I would get to this

part.

Only now I realize this situation, looking back at this period of my life

with pleasure and gratitude.

Finally, this moment will come. The examiners will evaluate the results of

this work, but I can certainly say that the process will be pleasant. So I am

glad to complete it by remembering many wonderful people who have

contributed to it in various ways.

My firsts thanks goes to God, for its constant presence in my life, for

guiding my choices and for the comfort in the difficult moments.

Sincere thanks to my supervisor, Prof. Emo Chiellini, who gave me the

opportunity to achieve this important objective.

I also thank the reading committee members who kindly agreed to read

my manuscript and to participate in this discussion.

Special thanks to Maria Viola, Michela Bianchi and Maria Caccamo.

Persons that help me in all situations!

Very special thanks to my tutor Dr: Elizabeth Grillo Fernandes (Beth) and

the Prof. Syed Imam; they had been so generous with their time. For all the

teachings, friendship, trust and patience I am truly grateful.

I would also like to thank several people from the DCCI and BIOLAB for

all time we spent together in these years; for share the good times and for the

help that gave me in the moments I needed. great colleagues like Elisa,

Matteo, Sara, Federica, Ahmed, Federica, Cristiano, Veska, Marcella,

Antonella, Sangram, Mamoni, Chiara, Andrea, Silvia, Patrizia, Giulia and all

the others that are too long to list.

Finally, I am greatly indebted to my family. A huge thanks to my parents,

Sauro and Vittoria, to my sister Lisa and her husband Roberto. Finally, a

truthful thanks to my husband Gabriele, for allowing me the time and space

to realize this project, for its love, support, advices and faith. A grateful

thanks to Aurora, my daughter, that she is the scope of my life and she

always gives me the forces and hopes to continue and to complete this work.

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INDEX

ACKNOWLEDGEMENTS

INDEX………………………………………………………………………..I

LIST OF ABBREVIATIONS…………………………………………....VII

LIST OF TABLES……………………………………………………….....X

LIST OF FIGURES………………………………………………………XV

ABSTRACT……………………………………………………………….XX

1. INTRODUCTION..................................................................................1

1.1. WASTE DISPOSAL ISSUES AND LEGISLATIVE BACKGROUND.............2

1.2. DISPOSAL OF ALGAE AND GROUND RICE..........................................7

1.3. POLYMERS FROM RENEWABLE RESOURCES ....................................10

1.4. POLYESTERS....................................................................................12

1.5. MULTILAYER PACKAGING FILMS....................................................14

1.6. TECHNOLOGY FOR BIOBASED POLYMER PROCESSING ....................16

OBJECTIVES 19

2. EXPERIMENTAL ...............................................................................25

2.1. MATERIALS.................................................................................26

2.1.1. Reagents and Solvents ............................................................26

2.1.2. Additives .................................................................................26

2.1.3. Fillers .....................................................................................26

2.2. POLYMERS ......................................................................................27

2.3. POLYMERS–NATURAL FIBRES COMPOSITES....................................29

2.3.1 Preparation of PHB/Ulva Composites ...................................29

2.3.2 Preparation of PCL/Ulva Composites ...................................30

2.3.3. Preparation of PHBPCL blends.............................................31

2.3.4 Preparation of PHBPCL/Ulva Composites............................32

2.3.5 Preparation of Hydrolene/Ground Rice Composites .............33

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2.3.6 Preparation of Hydrolene/Ground Rice/Calcium Carbonate

Composites. ............................................................................34

2.3.7 Preparation of Hydrolene/Ground Rice/Calcium Carbonate/

Calcium Sulphate Composites................................................35

2.3.8 Preparation of Hydrolene/Chaff and Flour Composites........36

2.3.9 Preparation of Hydrolene/PFc/Calcium Carbonate/Calcium

Sulphate Composites. .............................................................37

2.3.10 Preparation of Poly(lactic acid)/Bionolle Blends ..................38

2.4 POLY(HYDROXYALKANOATES) (PHAS) EXTRACTION AND

PURIFICATION .....................................................................................39

2.4.1 PHAs Pretreatment.................................................................39

2.4.2 PHAs Purification ..................................................................39

2.4.3 PHAs Solvent Extraction ........................................................40

2.5 DEWAXING OF LIGNO-CELLULOSIC MATERIALS.............................40

2.5.1 Sugar Cane Bagasse (SCB)....................................................40

2.5.2 Rice Straw (RS) ......................................................................42

2.6 ISOLATION OF WATER-SOLUBLE HEMICELLULOSE (WSH) WATER-

SOLUBLE LIGNIN (WSL).....................................................................44


2.7 ISOLATION OF CELLULOSE, ALKALINE-PEROXIDE-SOLUBLE

HEMICELLULOSE (APSH) AND ALKALINE-PEROXIDE-SOLUBLE LIGNIN

(ASL) FROM WATER-SOLUBLE FREE DEWAXED SUGAR CANE

BAGASSE (WSFR) ..............................................................................47


2.7.2 Rice Straw (RS) ......................................................................48

2.8 PHB–NATURAL FIBERS BLENDS ....................................................49

2.8.1 Acetylation of Cellulose..........................................................49

2.8.2 Production of Films by Casting..............................................50

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2.9 CHARACTERIZATION OF BUILDING BLOCKS, POLYMERS AND RELATIVE

BLENDS AND COMPOSITES ..................................................................50

2.9.1 Thermogravimetric Analysis (TGA) .......................................50

2.9.2 Differential Scanning Calorimetry (DSC)..............................51

2.9.3 Scanning Electron Microscopy (SEM) ...................................52

2.9.4 Wide Angle X-ray Scattering (WAXS) ....................................52

2.9.5 Gel Permeation Chromatography (GPC) ..............................53

2.9.6 Transmission Fourier Transform Infrared Spectroscopy

(FTIR) .....................................................................................53

2.9.7 Nuclear Magnetic Resonance (NMR).....................................53

2.9.8 Mechanical Tests ....................................................................53

2.9.9 Fiber Analyzer ........................................................................54

2.9.10 Mill .........................................................................................54

2.9.11 Brabender ...............................................................................55

2.9.12 Lab-Scale Double Screw Extruder .........................................55

2.9.13 Pilot-Scale Double Screw Extruder........................................55

2.9.14 Compression Moulding ..........................................................55

2.9.15 Density Measurements............................................................55

3 RESULTS .............................................................................................57

3.1 POLY(HYDROXYALKANOATES) FROM OLIVE OIL MILLS WASTEWATER:

CHARACTERIZATION AND LCA...........................................................58

3.1.1 Gel Permeation Cromatography ............................................62

3.1.2 Thermal Properties.................................................................64

3.1.2.1 Thermogravimetry (TGA)..................................................64

3.1.2.2 Differential Scanning Calorimetry (DSC) .........................71

3.1.3 FTIR Analysis .........................................................................72

3.2 LCA EVALUATION FOR THE PHAS OBTAINED FROM WASTEWATERS OF

OLIVE OIL MILL..................................................................................74

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3.3 CONCLUSIONS.................................................................................82

3.4 MODIFICATION OF CELLULOSE EXTRACTED FROM SUGAR CANE

BAGASSE (SCB) AND RICE STRAW (RS).............................................83

3.4.1 Chemical Composition ...........................................................85

3.4.2 Morphology of Lignocellulosic Wastes ..................................88

3.4.3 Thermal Properties of Lignocellulosic Materials ..................90

3.4.3.1 Thermogravimetric Analysis (TGA)..................................91

3.4.3.2 Differential Scanning Calorimetry (DSC) .......................108

3.4.4 Infrared Spectroscopy (FTIR) ..............................................109

3.5 CONCLUSIONS...............................................................................116

3.6 BLENDS BASED ON BIODEGRADABLE POLYMERS OF NATURAL AND

SYNTHETIC ORIGIN ...........................................................................118

3.6.1 PLABn Blends.......................................................................121

3.6.1.1 Thermal Properties...........................................................121

3.6.1.1.1 Thermogravimetric Analysis (TGA)............................121

3.6.1.1.2 Differential Scanning Calorimetry (DSC) ...................124

3.6.1.2 Mechanical Properties..................................................126

3.6.2 PHB/Cellulose Acetate (CA) ................................................129

3.6.2.1 Morphology......................................................................129

3.6.2.2 Thermal Properties...........................................................130



3.6.2.3 Wide Angle X-ray Diffraction (WAXS)......................136

3.7 CONCLUSIONS...............................................................................136

3.8 COMPOSITES BASED ON BIODEGRADABLE MATERIALS AND NATURAL

ORGANIC FILLERS.............................................................................138

3.8.1 Organic Fillers .....................................................................142

3.8.1.1 Ulva Fibres.......................................................................142

3.8.1.1.1 Morphology..................................................................142

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3.8.1.1.2 Thermal Properties .......................................................143

3.8.1.1.3 Infrared Spectroscopy ..................................................144

3.8.1.2 Ground Rice, Chaff and Farinaccio .................................146

3.8.1.2.1 Morphology..................................................................146


3.8.1.2.3 Infrared Spectroscopy (FTIR) ......................................152

3.8.1.3 Polymeric Materials .........................................................154


3.8.1.4 Composites based on PCL/ulva .......................................158

3.8.1.4.1 Morphology..................................................................158



3.8.1.4.4 Mechanical Properties..................................................165

3.8.1.5 Composites based on PHB/Ulva ......................................166

3.8.1.5.1 Morphology..................................................................166




3.8.1.6 Composites based on PHB/PCL ......................................171




3.8.1.4 Composites based on PHBPCL/Ulva...............................177




3.8.1.8 Composites based on Hydrolene/Ground Rice ................183

3.8.1.8.1 Morphology..................................................................183


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3.8.1.9 Composites based on LFT/FR/CaCO3 .............................188

3.8.1.9.1 Morphology..................................................................188



3.8.1.10 Composites based on LFT/FR/CaCO3/CaSO4 .................192

3.8.1.10.1 Morphology..................................................................192


3.8.1.11 Composites based on LFT/PHB/PFc/CaCO3/CaSO4.......194

3.8.1.11.1 Morphology..................................................................194


3.9 CONCLUSIONS...............................................................................197

4 THE FOAMING AGENTS...............................................................201

5 EFFERVESCENT MATERIALS ....................................................215

5.1 CONCLUSIONS...............................................................................222

CONCLUSIONS………………………………………………………….223

REFERENCES 225

vii

LIST OF ABBREVIATIONS

ASH Alkaline-Peroxide Soluble Hemicellulose

ASL Alkaline-Peroxide Soluble Lignin

Bn Bionolle

CA Cellulose Acetate

∆Cp Specific Heat

CaCO3 Calcium Carbonate

CaSO4 Calcium Sulphate

C-SCB Chopped Sugar Cane Bagasse

C-RS Chopped Rice Straw

DAGA Department of Agronomy and Agrosystem Management

DSC Differential Scanning Calorimetry

DC-SCB Dewaxed Chopped Sugar Cane Bagasse

DM-SCB Dewaxed Milled Sugar Cane Bagasse

DC-RS Dewaxed Chopped Rice Straw

DM-RS Dewaxed Milled Rice Straw

DS Degree of Substitution

DTGA Derivative Thermogravimetric Analysis

EC European Community

EEA European Energy Agency

El Elastic Modulus

Fc Flour

FeO Iron Oxide

FR Ground Rice

FTIR Transmission Fourier Transform Infrared Spectroscopy

FU Function Unit

GPC Gel Permeation Cromatography

∆Hcc Cold Crystallization Enthalpy

∆Hm Enthalpy of Fusion

ICTA International Confederation for Thermal Analysis

viii

LCA Lyfe Cycle Assessment

LFT Hydrolene

Min Minutes

Mn Number Average Molecular Weight

Mw Weight Average Molecular Weight

Mw/Mn Polydispersivity Index

M-RS Milled Rice Straw

M-SCB Milled Sugar Cane Bagasse

NMR Nuclear Magnetic Resonance

OMW Olive Oil Mills Wastewater

P Pressure

PAR Pilot Aerobic Reactor

PCL Poly-Caprolactone

PET Poly-(ethylene)-terephalate

PFc Chaff-Flour Mixture

PHAs Poly-(Hydroxy)-Alkanoates

PHB Poly-(hydroxy)-butirrate

PLA Poly-Lactic Acid

PP Pilot Plant

PS Polystyrene

PVA Poly-(Vinyl)-Alcohol

R Residue

RS Rice Straw

SAR Small Aerobic Reactor

SCB Sugar Cane Bagasse

SEM Scanning Electron Microscopy

StDv Standard Deviation

T Temperature

Tcc Cold Crystallization Temperature

Td Decomposition Temperature

Ton Onset Temperature

Tp Degradation Temperature

ix

T2% Degradation Temperature Corresponding 2 % Weight Loss in the

Sample

Tg Glass Transition Temperature

Tm Melting Temperature

TGA Thermogravimetric Analysis

U Ulva

UTS Ultimate Tensile Strenght

V Speed

∆W Weight Loss

WAXS Wide Angle X-Ray Spectroscopy

WSFR Water Soluble Free Residue

WSH Water Soluble Hemicellulose

WSL Water Soluble Lignin

ZnO Zinc Oxide

YM Young Modulus

x

LIST OF TABLES

Table 2.1 Compositions and Processing Conditions of PHB/Ulva

Composites.

Table 2.2 Double Screw Extruder Working Parameters.

Table 2.3 Compositions and Working Conditions of PCL/Ulva

Composites.

Table 2.4 Compositions and Working Conditions of PHBPCL Blends.

Table 2.5 Compositions and Working Conditions of PHBPCL/Ulva

Composites.

Table 2.6 Compositions and Working Conditions for LFTFR

Composites.

Table 2.7 Double Screw Extruder Working Parameters.

Table 2.8 Compositions and Working Conditions of LFT/FR/CaCO3

Composites.

Table 2.9 Compositions and Working Parameters of

LFT/FR/CaCO3/CaSO4 Composites.


Hydrolene/Chaff/Flour Composites.


Hydrolene/PFc/CaCO3 /CaSO4 Composites.

Table 2.12 Compositions and Working Parameters of PLABn Blends.

Table 3.1 Samples Produced by Pseudomonas Strain.

Table 3.2 Samples Produced by Azotobacter Sp with a Small Aerobic

Reactor.

Table 3.3 Samples Produced by Azotobacter Sp with a Pilot Plant.

Table 3.4 Mw (kDa) of SAR-3 and SAR-4.a

Table 3.5 Mw (kDa) of 72h and 96h

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Table 3.6 TGA Parameters in Nitrogen Atmosphere of PHAs Produced

by Pseudomonas Strain.a


by Azotobacter Sp Using a Small Aerobic Reactor.a


by Azotobacter Sp Using a Pilot Plant.a


by Azotobacter Sp at 72h and 96h.a

Table 3.10 Thermodynamic Parameters of PAR-7 (Second Heating).a

Table 3.11 Assignments of PHAs main FT-IR Absorption Bands(29-32).

Table 3.12 Biomass and Polymer Concentration in the Culture Media,

Polymer Content in the Biomass and Culture Media Needed

for 1 kg of PHAs.

Table 3.13 Chemical Composition (wt-%) of Egyptian Sugar Cane

Bagasse.

Table 3.14 Chemical Composition (wt-%) of Egyptian Rice Straw.

Table 3.15 Thermogravimetric Data of SCB Based Materials Under

Nitrogen Atmosphere.

Table 3.16 Thermogravimetric Data of SCB Based Materials Under Air

Atmosphere.

Table 3.17 Thermogravimetric Data for RS Based Materials Under


Table 3.18 Thermogravimetric Data for Cellulose, D-SCB, SCB and

WSFR Under Nitrogen Atmosphere.

Table 3.19 Thermogravimetric Data for Cellulose and Cellulose Acetate

(CA) Under Nitrogen Atmosphere.

Table 3.20 Thermogravimetric Data for Cellulose and Cellulose Acetate

(CA) Under Air Atmosphere.

Table 3.21 Thermogravimetric Data for Alkaline Peroxide Soluble

Hemicellulose (APSH) Under Nitrogen and Air Atmosphere.

xii

Table 3.22 Thermogravimetric Data for Alkaline Soluble Lignin (ASL)

Under Nitrogen and Air Atmosphere.

Table 3.23 FTIR Absorption Frequencies of Functional Groups in the

Alkaline-Peroxide-Soluble Hemicellulose (APSH).


Alkaline-Peroxide-Soluble Lignin (ASL).

Table 3.25 Thermogravimetric Data for PLABn Blends Under Nitrogen

Atmosphere.

Table 3.26 Thermodynamic Properties for PLABn Blends.

Table 3.27 Mechanical Properties for PLABn Blends.

Table 3.28 Thermogravimetric Data for CA/PHB Blends Under Nitrogen

Atmosphere.

Table 3.29 Thermodynamic Properties for PHB, Cellulose Acetate (CA)

and their Blends.

Table 3.30 Micronized Ulva Fibres Distribution.


Micronized Ulva.

Table 3.32 Ground Rice Granules Distribution.

Table 3.33 Chaff Granules Distribution.

Table 3.34 Farinaccio Granules Distribution.

Table 3.35 Thermogravimetric Data for the Fibres Under Nitrogen

Atmosphere.


Ground Rice.


Chaff.


Farinaccio.

Table 3.39 Thermogravimetric Data for the Polymeric Materials Under


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Table 3.40 Thermodynamic Properties for Polymeric Materials.

Table 3.41 Thermogravimetric Data for the PCL/Ulva Composites.

Table 3.42 Thermodynamic Properties for PCL/Ulva Composites.

Table 3.43 Mechanical Properties for the PCL/Ulva Composites.

Table 3.44 Thermogravimetric Data for the PHB/Ulva Composites.

Table 3.45 Thermodynamic Properties for the PHB/Ulva Composites.

Table 3.46 Mechanical Properties for PHBU20 and PHBU30 Composites.

Table 3.47 Thermogravimetric Data for the PHBPCL Composites.

Table 3.48 Thermodynamic Properties for the PHBPCL Composites.

Table 3.49 Mechanical Properties for the PHBPCL Composites.

Table 3.50 Thermogravimetric Data for the PHBPCL/Ulva Composites.

Table 3.51 Thermodynamic Properties for the PHBPCL/Ulva

Composites.

Table 3.52 Mechanical Properties for the PHBPCL/Ulva Composites.

Table 3.53 Thermogravimetric Data for the LFTFR Composites.

Table 3.54 Thermodynamic Properties for the LFTFR Composites.

Table 3.55 Thermogravimetric Data for the LFT/FR/ CaCO3 Composites.

Table 3.56 Thermodynamic Properties for the LFT/FR/CaCO3

Composites.

Table 3.57 Thermogravimetric Data for the LFT/FR/CaCO3/CaSO4

Composites.

Table 3.58 Thermogravimetric Data for the LFT/PHB/PFc/CaCO3/CaSO4

Blends.

Table 3.59 Main Foaming Agents by Alqemia Group.

Table 3.60 Product Description.

Table 3.61 MILLIFOAM Product Range.

xiv

LIST OF FIGURES

Figure 1.1 Main Options for the Production of Environmentally

Degradable Bio-Based Polymeric Materials and Plastics.

Figure 2.1 Example of Non Purified (a) and Purified (b) Biomass.

Figure 2.2 Dewaxing of Sugar Cane Bagasse (SCB) Using a Kumagawa

Extractor (a) and Dewaxing Step-by-Step (b).

Figure 2.3 Apparatus for the Sugar Cane Bagasse Dewaxing.

Figure 3.1 GPC Trace (RI detector) of PAR-7.

Figure 3.2 GPC Traces of SAR-1, SAR-2, SAR-3 and SAR-4.

Figure 3.3 GPC Traces of 72h and 96h.

Figure 3.4 TGA (a) and DTGA (b) Traces of PHAs Produced by

Pseudomonas Strain.

Figure 3.5 TGA (a) and DTGA (b) Traces Under Nitrogen Atmosphere

of PHAs Produced by Azotobacter Sp using a Small Aerobic

Reactor.

Figure 3.6 TGA and DTGA Traces of PHAs Produced by Azotobacter Sp

Using a Pilot Planta.

Figure 3.7 TGA (a) and DTGA (b) Traces Under Nitrogen Atmosphere

of PHAs Produced by Azotobacter Sp at 72h and 96h.

Figure 3.8 Second Heating DSC Traces of PAR-7 (a) and 72h-96h (b).

Figure 3.9 FT-IR Spectra of PHAs Produced by Pseudomonas Strain.

Figure 3.10 FT-IR Spectra of PP-1 at 72h and 96h.

Figure 3.11 System Boundaries of Traditional Technologies for PHAs

Production and OMW Treatment.

Figure 3.12 System Boundaries of POLYVER Technologies for PHAs


Figure 3.13 Schematization of System Expansion Approach.

xv

Figure 3.14 Input/Output Analysis of PHAs Purification and Extraction.

Figure 3.15 SEM Photomicrographs for M-SCB-35X (a), DM-SCB-37X

(b), C-SCB-43X (c), DC-SCB-35X (d).

Figure 3.16 SEM Photomicrographs for M-RS-100X (a), DM-RS-50X (b),

C-RS-220X (c), DC-RS-150X (d).

Figure 3.17 SEM Photomicrographs for Cellulose from SCB-550X (a),

Cellulose Acetate-50X (b), WFSR-95X (c).

Figure 3.18 TGA (a) and DTGA (b) Traces of SCB Based Materials

Under Nitrogen Atmosphere.

Figure 3.19 TGA (a) and DTGA (b) traces of M-SCB, C-SCB, DM-SCB,

and DC-SCB under air atmosphere.

Figure 3.20 TGA (a) and DTGA (b) Traces of M-RS, C-RS, DM-RS, and

DC-RS Under Nitrogen Atmosphere.

Figure 3.21 TGA (a) and DTGA (b) Traces for RS Based Materials Under

Air Atmosphere.

Figure 3.22 TGA (a) and DTGA (b) Traces of SCB, DSCB, WSFR, and

Cellulose Under Nitrogen Atmosphere.

Figure 3.23 TGA (a) and DTGA (b) Traces of Cellulose, and Cellulose

acetate (CA) Under Nitrogen Atmosphere.

Figure 3.24 TGA (a) and DTGA (b) Traces for Cellulose and Cellulose

Acetate (CA) Under Air Atmosphere.

Figure 3.25 TGA (a) and DTGA (b) Traces of Alkaline Peroxide Soluble


Figure 3.26 TGA (a) and DTGA (b) Traces of Alkaline Soluble Lignin

(ASL) Under Nitrogen and Air Atmosphere.

Figure 3.27 DSC Traces of Cellulose and Cellulose Acetate (CA) (Second

Heating).

Figure 3.28 DSC Traces of SCB based Materials (Second Heating).

Figure 3.29 DSC traces of RS based Materials (Second Heating).

xvi

Figure 3.30 FTIR Spectra of M-SCB, C-SCB, DM-SCB, and DM-SCB (a)

and FTIR Spectra of SCB Before and After Dewaxing,

Cellulose, WFSR (b).

Figure 3.31 FTIR Spectra of M-RS, C-RS, DM-RS, and DC-RS.

Figure 3.32 FTIR Spectra of Cellulose, and Cellulose Acetate (CA).

Figure 3.33 FTIR Spectra of Alkaline Peroxide Soluble Hemicellulose

(APSH) (a) and Alkaline Peroxide Soluble Lignin (b) (ASL).

Figure 3.34 TGA (a) and DTGA (b) Traces for PLABn Blends.

Figure 3.35 DSC Traces for PLABn Blends.

Figure 3.36 Mechanical Properties Traces for PLABn Blends.

Figure 3.37 SEM Photomicrographs for CA/PHB (20/80)-4000X (a),

CA/PHB (40/60)-2200X (b), CA/PHB (50/50)-1300X (c),

CA/PHB (60/40)-4000X (d).

Figure 3.38 TGA (a) and DTGA (b) Traces for CA/PHB Blends.

Figure 3.39 DSC Traces for PHB, Cellulose Acetate (CA) and CA/PHB

Blends.

Figure 3.40 WAXS Diffraction Patterns of CA/PHB Blends.

Figure 3.41 SEM Photomicrograph for Micronized Ulva-250X.

Figure 3.42 TGA and DTGA Traces for Ulva Fibres.

Figure 3.43 Ulva IR Spectrum.

Figure 3.44 SEM Photomicrograph for Ground Rice-200X.

Figure 3.45 SEM Photomicrograph for Chaff-200X.

Figure 3.46 SEM Photomicrograph for Farinaccio-150X.

Figure 3.47 TGA and DTGA Traces of Ground Rice.

Figure 3.48 TGA and DTGA Traces of Chaff and Farinaccio.

Figure 3.49 Ground rice IR Spectrum.

Figure 3.50 Chaff IR Spectrum.

Figure 3.51 Farinaccio IR Spectrum.

Figure 3.52 TGA and DTGA Traces of Hydrolene (a) and PVA 18/88 (b).

Figure 3.53 TGA and DTGA Traces of PHB (a) and PCL 6500 (b).

xvii

Figure 3.54 TGA and DTGA Traces of PLA.

Figure 3.55 SEM Photomicrographs for PCL-1000X (a) and PCLU30-

1000X (b).

Figure 3.56 TGA (a) and DTGA (b) Traces for PCL/Ulva Composites.

Figure 3.57 Ton and Residue Trend for PCL/Ulva Composites.

Figure 3.58 DSC Traces for PCL/Ulva Composites.

Figure 3.59 SEM Photomicrographs for PHBU30-1000X (a), and

PHBU50-1000X (b) Composites.

Figure 3.60 TGA (a) and DTGA (b) Traces for PHB/Ulva Composites.

Figure 3.61 DSC Traces for the PHB/Ulva Composites.

Figure 3.62 TGA (a) and DTGA (b) Traces for PHBPCL Composites.

Figure 3.63 DSC Traces for the PHBPCL Composites.

Figure 3.64 Elongation at Break, Ultimate Tensile Strength and Young

Modulus for the PHBPCL Composites.

Figure 3.65 TGA (a) and DTGA (b) Traces for the Composite

(PHB80PCL20)Ulva.

Figure 3.66 TGA (a) and DTGA (b) Traces for the (PHB80PCL20)Ulva

Composite.

Figure 3.67 DSC Traces for the PHBPCL/Ulva Composites.


Modulus for the PHBPCL/Ulva Composites.

Figure 3.69 SEM Photomicrographs for LFTFR30-1700X (a), and

LFTFR50-1700X (b) Composites.

Figure 3.70 TGA (a) and DTGA (b) Traces for the LFTFR Composites.

Figure 3.71 DSC Traces for the LFTFR Composites.

Figure 3.72 SEM Photomicrographs for LFTFR40CaCO35-450X (a), and

LFTFR40CaCO325-450X (b) Composites.

Figure 3.73 TGA (a) and DTGA (b) Traces for LFT/FR/CaCO3

Composites.

Figure 3.74 DSC Traces for the LFT/FR/CaCO3 Composites.

xviii

Figure 3.75 SEM Photomicrograph for the LFTFR40CaCO3_CaSO45-

500X Composite.

Figure 3.76 TGA (a) and DTGA (b) Traces for LFT/FR/CaCO3/CaSO4

Composites.

Figure 3.77 SEM Photomicrographs for LFT10/PHB30/PFc20/C30/G10-

80X (a) and LFT10/PHB5/PFc20/C55/G10-50X (b)

Composites.

Figure 3.78 TGA (a) and DTGA (b) Traces for the

LFT/PHB/PFc/CaCO3/CaSO4 Blends.

xix

ABSTRACT

The study of this thesis was focused on natural materials of marine origin

such as algae or seaweeds and lignocellulosic materials such as sugar cane

bagasse (SCB) and rice straw (RS).

The aim was to make an improve for the mechanical properties of the

polymer blending it with the selected natural fillers to obtain composites and

objects that can be competitive with the conventional ones and so introduced

on the market.

This work was structured in three chapters, where the latter reports all the

obtained results divided in six sections. In the first section, the

polyhydroxyalkanoates (PHAs) production from olive oil mills wastewater,

their characterization and Lyfe Cycle Assessment (LCA) were studied.

For this purpose, a screening of the traditional methods and carbon source

to obtain PHAs from biomasses, was conducted, in order to plan a

POLYVER technology.

The variables selected were four bacterial strains processed in a Pilot

Aerobic Reactor (PAR), in a Small Aerobic Reactor (SAR) and in a Pilot

Plant (PP) in accord to the LABOR (Rome) protocol.

The PHAs were characterized by means of thermal analysis (TGA and

DSC), gel permeation chromatography (GPC) and Fourier Transform

Infrared Spectroscopy (FTIR).

In the second section, the cellulose extracted from sugar cane bagasse and

rice straw was modified by the acetylation process obtaining cellulose

acetate.

The starting raw materials were dried and submitted to a dewaxing process

using a Kumagawa extractor and toluene/ethanol (2:1) as a solvent mixture.

SCB and RS, before and after dewaxing, were characterized by means of

scanning electron microscopy (SEM), TGA, DSC and FTIR.

xx

Some chemical procedures were used to isolate the material components

(cellulose, alkaline peroxide soluble hemicellulose, alkaline peroxide soluble

lignin, WSFR). The cellulose and its acetylated product that is cellulose

acetate were characterized by means of SEM, TGA, DSC, FTIR and wide

angle x-ray scattering (WAXS).

The FTIR technique was used for the determination of the substitution

degree (DS) of the acetylated product (DS=2.7).

The third section comprises two series of experiments concerning the

production of blends based on biodegradable polymers, natural and synthetic.

Two different types of blends were produced: polylactic acid-Bionolle

(PLABn) and cellulose acetate-polyhydroxybutirrate (CA/PHB) blends.

The first type was obtained by compression moulding and the second was

produced by film casting.

PLABn blends were characterized by means of TGA, DSC and tensile test

(Instron), while CA/PHB blends were characterized by means of SEM, TGA,

DSC and wide angle x-ray scattering (WAXS).

The fourth section analyzed the production and the characterization of

composites based on biodegradable polymers and natural organic fillers.

Some types of composites were produced using algae, ground rice and its

by-products as natural fillers and PHB, PCL, hydrolene as biodegradable

polymers by extrusion or compression moulding. These composites were

evaluated for dimensional (ASTM distribution), morphological (SEM,

FTIR), thermal (TGA, DSC) and mechanical properties.

The obtained results showed that the ground rice improved the adhesion

between the filler and the polymeric matrix. The mechanical properties of the

Ulva family showed an increase for the Young Modulus and a decrease for

the Elongation at Break and the Ultimate Tensile Strenght.

The fifth and sixth sections reported the background for the foaming

agents and the effervescent materials.

Introduction

1

1. INTRODUCTION

PhD Thesis – Arianna Barghini

2

The European Environmental Agency (EEA)(1) has conducted some

studies concerning the achievement of the material wealth levels that are

similar to today’s levels in industrialised and developing countries.

Naturally, world consumption of resources would increase by a factor

ranging from two to five and a huge growing municipal and industrial wastes

will have to be handled.

Waste consists of a mix of very different materials, that have their own

characteristics, environmental impact, recycle and re-use options.

The inevitable waste resulting from plastic goods and packaging are found

all over the world. Plastics are relatively cheap, durable and versatile

materials.

However, when they are transformed in waste they constitute a sizeable

percentage of the litter. Besides, many of the plastics are also non-

biodegradable or they are difficult to re-use and/or recycle, and they may

represent risks to human health and to environment. The demand for green

packaging will approach $45 billion in 2013. The largest markets for green

packaging are food, consumer products and beverages, that together

represented two thirds of total green packaging demand in 2008.

However, the fastest growing markets through 2013 will be the

foodservice and shipping markets(2).

1.1. Waste Disposal Issues and Legislative Background

The greatest environmental pressure for the packaging chain comes from

legislation. According to the European Environmental Agency(1,5-9),

packaging waste is the major and growing waste stream. Its amounts has

increased in most European countries despite the agreed objective of the

waste prevention. The projections show that packaging waste amounts will

arrive at 77 million tonnes in 2008.

Introduction

3

A well-known example at European level is the EC Directive on

Packaging Wastes. This directive stipulates that “packaging shall mean all

products made of any materials of any nature to be used for the containment,

protection, handling, delivery and presentation of goods, from raw materials

to processed goods, from the producer to the user or the consumer.

Non–returnable items used for the same purposes shall also be considered

to constitute packaging”(3). “Packaging waste shall mean any packaging

material covered by the definition of waste in Directive 75/442/EEC,

excluding production residues” and “waste means any substance or object

which the holder disposes of or it is required to dispose of pursuant to the

provisions of national law in force”(4).

The solid waste is disposed in open dumps and landfills and it generates

methane and other gases. Many countries regularly capture LFG as a strategy

to improve landfill safety, generate electricity, reduce greenhouse gas

emissions, and to earn carbon emission reduction credits(159).

The volatility of the market and the energy prices(168), the declining

production rates, and the recent geopolitical acts of war and terrorism were

underscored the vulnerability of the current global energy system to supply

disruptions.

According to World Energy Outlook (2008), current energy supplies were

unsustainable from environmental, economic, and societal standpoints.

In addition, it was projected that world energy demands will continue to

expand by 45 % from 2008 to 2030, with an increased average rate of 1.6 %/yr.

In 2007, the intergovernmental panel on climate change (IPCC 2007)

released its fourth assessment report confirming that the climate change was

accelerating and if the current trends continued, energy-related emissions of

carbon dioxide (CO2) and other greenhouse gases will rise inexorably, pushing

up average global temperature by as much as 6°C in the long term.


4

Recent floods, cyclones, tsunamis, sea rise, droughts, and famines

throughout the world were implicated as a part of climate change resulting

from unabated burning of fossil fuels (IPCC 2008). This situation had a strong

impact on the threatens water, the food production, the human health and the

quality of land on a global scale (OCC 2006; IPCC 2008). Preventing

catastrophic and irreversible damage to the global climate ultimately required a

major decarbonization drive.

Globally, 80 % of total primary energy supply depended on the fossil fuels

coal, gas, and petroleum-based oils. Renewable energy sources represented

only 13 % of total primary energy supply currently, with biomass (the material

derived from living organisms) dominating with 10 % in renewable sector

(IEA 2007a).

Traditional biomass, including fuel wood, charcoal, and animal dung,

continued to provide important sources of bio-energy for most of the world

population who live in extreme poverty and who used this energy mainly for

cooking. More advanced and efficient conversion technologies now allow the

extraction of bio-fuels in solid, liquid, and gaseous forms from a wide range

of biomass sources such as woods crops and biodegradable plant and animal

wastes. Bio-fuels can be classified according to source, type and

technological process of conversion under the categories of first, second,

third and fourth generation bio-fuels.

First generation of bio-fuels are products made from biomass consisting of

sugars, starch, vegetable oils, animal fats, or biodegradable output wastes

from industry, agriculture, forestry, and households using conventional

technologies. Second generation is derived from lignocellulosic biomass

using a liquid technology, including cellulosic bio-fuels from non-food crops

such as the stalks of wheat, corn, wood, and energy-dedicated biomass crops,

such as miscanthus.

Many of them are under development such as bio-hydrogen, bio-methanol,

Introduction

5

dimethyl furan, dimethyl ether, Fischer–Tropsch diesel, bio-hydrogen diesel,

mixed alcohols, and wood diesel.

Third generation is in the nascent stage of development and it is derived

from low input/high output production organisms such as algal biomass.

Fourth generation is derived from the bioconversion of living organisms

(micro-organisms and plants) using biotechnological tools(169,170).

National governments are setting targets and developing strategies,

policies, and investment plans in bio-fuels to enhance energy security and

exploit alternative energy to mitigate CO2 emission. The recent increase of

oil prices, energy security fears, and the domestic reform of agricultural

policies give cause for a more serious consideration of bio-fuel in most of

countries. USA, Europe, and Brazil are leading proponents of these

initiatives. Mandates for blending bio-fuel into vehicle fuels were enacted in

at least 37 countries(171). In developed countries, government support for the

domestic production of energy crops for bio-fuel seemed to be the rule(172).

In the USA, estimated subsidies to the bio-fuel industry might reach US

$13 billion in 2008 and federal tax credit could cost US $19 billion/yr by

2022(173) while in the European Union (EU), bio-fuel support of €0.52/l will

end up costing its tax payers €34 billion/yr(174-176).

These initiatives contributed to the rapid growth of liquid bio-fuels in

terms of volume and share of transport fuels. Since 2001, bio-fuel production

was increased almost six fold to 6 billion litres in 2006 and it was projected

to grow to 3.0–3.5 % of total global transport energy by 2030 from the

present 1.9 %(177,178). However, environmental groups were raising concerns

about the trade-off in food vs. fuel and effectiveness of bio-fuels in

mitigating green house gas emissions.

Recent rise in food prices, shortage of food, conflicting demands of arable

land, heavy use of fertilizers for bio-fuel production, and deforestation of rain

forests escalated the debate to a global scale(170,176,178-181). On the other hand,


6

several studies showed that bio-fuel production can be significantly increased

without affecting food crops. Further reports suggested that Brazil’s sugar-

based ethanol production had not contributed to the food crisis(182-185).

Others suggested that the success of second and third generation

technologies dealing with non-food biomass will play much bigger role than

expected in coming years(171,186).

Another legislation example is the Norwegian Public Roads

Administration, which has been chosen a way to obtain more practical

acceptance criteria for recycled materials in road construction(236).

The approach was based on a combination of the European standard for

characterization of waste, ENV 12920, and Guidelines for evaluating impact

on health and ecosystem; SFT 99:01, issued by the Norwegian Pollution

Control Authority.

Norwegian conditions concerning natural resources and waste were

described with the aim of pointing out major differences from European

countries that had achieved high recycling levels.

One reason for the low level of recycling in this area was the abundance of

high quality and relatively low cost natural aggregates and the ambitious

environmental policy settted high standards for pollution control and raised

concern regarding potential damage caused by long-term leaching.

However, implementation of uniform acceptance criteria according the

methods described might increase the rate of recycled materials used in road

construction.

Introduction

7

1.2. Disposal of Algae and Ground Rice

Anaerobic degradation or digestion is a biological process where organic

carbon is converted by subsequent oxidations and reductions to its most

oxidized state (CO2), and its most reduced state (CH4). A wide range of

micro-organisms can catalyze the process in the absence of oxygen; so the

main products of the process are carbon dioxide and methane, but minor

quantities of nitrogen, hydrogen, ammonia and hydrogen sulfide (usually less

than 1 % of the total gas volume) are also generated(163).

The mixture of gaseous products is termed biogas and the anaerobic

degradation process is often also termed the biogas process. As the result of

the removal of carbon, organic bound minerals and salts are released to their

soluble inorganic form. The biogas process is a natural process and it occurs

in a variety of anaerobic environments, such as marine and fresh water

sediment, sewage sludge, mud, etc.

The interest in this process is mainly due to the following two reasons,

that are an high degree of reduction of organic matter that is achieved with a

small increase, compared to the aerobic process, in the bacterial biomass;

the production of biogas, that can be utilized to generate different forms of

energy (heat and electricity) or be processed for automotive fuel.

The biogas process was known and utilized for many years, but especially

after the rise of energy prices in the 1970s, the process received renewed

attention due to the need to find alternative energy sources to reduce the

dependency on fossil fuels. Although the price of fossil fuels decreased in

1985, the interest in the biogas process still remained due to the

environmental benefits of anaerobic waste degradation. Additionally, the

biomass used for biogas production was originally produced by

photosynthetic fixation of carbon dioxide from the atmosphere, and


8

combustion of biogas thus did not add extra carbon dioxide to the atmosphere

as it did when combusting fossil fuels formed millions of years ago.

The anaerobic degradation process was used for years for energy

production and waste treatment. It was used in closed systems where optimal

and controlled conditions can be maintained for the micro-organisms.

The process can be utilized for the fast and efficient degradation of

different waste materials. The anaerobic process is today mainly utilized in

four sectors of waste treatment:

1. Treatment of primary and secondary sludge produced during the aerobic

treatment of municipal sewage. The process is utilized to stabilize and reduce

the final amount of the sludge and at the same time biogas is produced, that

can be used to partly cover the need for energy in the sewage treatment plant.

This application is widespread in the industrialized world connected with

the establishment of the advanced treatment systems for domestic

wastewater.

2. Treatment of industrial wastewater produced from biomass, food

processing or fermentation industries. These wastewater types are often

highly loaded and they can successfully be treated anaerobically before

disposal directly to the environment or sewage system. The produced biogas

can often be utilized to cover the need for process energy. With the

environmental concerns and cost of alternative disposal this application of the

anaerobic process is increasing.

3. Treatment of livestock waste in order to produce energy and improve

the fertilizing qualities of manure. Due to more strict rules concerning the

usage, distribution, and storage of manure this application is growing

especially in countries with an high animal production density.

4. A relatively new sector for use of the anaerobic processes on an

industrial scale is the treatment of the organic fraction of municipal solid

waste (OFMSW).

Introduction

9

The aim of this process is first of all to reduce the amount of waste in the

other treatment systems, i.e. landfills and incineration plants, and secondly to

recycle the nutrients from this type of waste to the agricultural sector.

European Community must find a resolution for two environmental

problems that are the algal proliferations and the elimination of the plastic

waste.

Sudden growth and uncontrolled proliferation of algae and sea weeds was

occurred in several costal regions due to many environmental factors such as

climate changes and particularly the eutrophyzation of sea water induced by

the agriculture and the farmers practices. Collection and storing of the algal

material represent a problem for many communities.

Very limited prior art has been found on the use of algae for the

production of bio-composite materials. US56564103A and WO00/1106

patents dealt with the use of algae for the production of respectively films

and foamed articles for packaging applications.

Some articles studying algae structure considered their applications as

filler in composite materials. Extracts from algae were used as emulsifier and

flow agents (68).

Ground rice is an italian material based on starch, easily processable and

characterized by a low cost. It is used as food resource for the animals.


10

1.3. Polymers from Renewable Resources

The term “polymers from renewable resources” refers to natural products

that are polymeric in character as grown or they can be converted to

polymeric materials by conventional or enzymatic synthetic procedures(104).

Thus under that heading one can include natural polymers used as direct

feedstock for plastic production as well as artificial polymers as those

obtained by chemical modification of preformed natural polymers or by

polymerization of monomers deriving from renewables(105,106).

The compostability is independent of the resources used as raw materials.

The “biodegradability” of plastics is dependent on the chemical structure

of the material and on the constitution of the final product, but not on the

resources used for its production. This fact is proven both scientifically and

technically. Therefore, the market should decide which raw material is best

for the respective biodegradable plastics application(107).

By the way there is an increasing pressure for a wider utilization of

biomass feed-stocks for speciality items. The total biomass produced on earth

is estimated as approximately 170 billion tons, and it consists of 75 %

carbohydrates, 20 % lignin and 5 % other natural products such as oils, fats,

proteins, terpenes, alkaloids and nucleic acids. Only about 3.5 % of this

biomass are used by man world-wide, with one-third being wood, one-third

cereals and one-third other products like oil seeds, sugar beets and sugar

cane, fruits and vegetables(108,109).

The major options for the production of polymeric materials specifically

meant to be converted to plastic items that should eventually experience

environmental degradation after the service life, are pointed out in Figure 1.1.

Introduction

11

Figure 1.1. Main Options for the Production of Environmentally

Degradable Bio-Based Polymeric Materials and Plastics.


12

1.4. Polyesters

Biodegradable polyesters and aliphatic or aromatic co-polyesters,

comprising aromatic poly-functional acid and aliphatic acid, as azelaic (≥ 50

% ), sebacic (≥ 70 %), brassylic acid (≥ 90 % ) and a diol component selected

from C3, C4, C6 diols(103), were also used in food packaging applications.

Chemical and mechanical properties of poly-hydroxybutirate (PHB),

wheat and corn starch were extensively investigated. Permeability O2/CO2

was 1:7 for poly-lactic acid (PLA) and 1:12 for PHB so it made possible to

render these materials suitable for packaging of food with high

respiration(110).

PLA has received much attention in the last decade because of its

originating from renewable resources and its potential biodegradability.

The packaging industry’s requirements are the realization of rigid objects

and soft films if a plasticizer is added to PLA(111).

The obtained films were studied by tensile testing, differential scanning

calorimetry (DSC), permeation of carbon dioxide, oxygen and water

vapour(100), showing that the choice of plasticizers was limited by the

requirements of the application in food packaging, like being non-toxic

substances approved for food contact, low migration rates and good

miscibility with PLA by creating an homogeneous blend(112).

PLA films have better UV light barrier properties than polyethylene but

they are worse than those of cellophane, polystyrene (PS) and

polyethyleneterephtalate (PET). NatureWorks PLA is suitable as food

packaging material and it can be recycled back to a monomer and into

polymers. It is fully compostable in industrial facilities, where it breaks down

like other matter derived from plants(113). Recycled PLA provides an

opportunity for full material utilization and lower costs in applications

concerning the maintenance of fresh food.(98).

Introduction

13

The effect of moisture sorption on stability of PLA films at food

packaging conditions obtained at different humidity and temperature was

investigated by decrease in numeral average molecular weight and loss of

tensile strength. PLA was expected to be mechanically stable when

packaging foods covering the region from dry to moist food and storage

conditions from chill to ambient temperatures(114).

PLA biopolymer showed an improvement of packaged food quality and

safety by increasing the barrier properties to oxygen of an ethylene-vinyl

alcohol copolymer in dry and under humid conditions(115). PLA treatments

inhibited the growth of E.coli by a spray method(116).

The extrusion polymerized process is a catalytic system that can be used

to produce PLA continuously in larger quantities with lower costs(117).

Blends of a non crystalline PLA polymer and a crystalline PLA polymer

were suitable for blister containers, food and packaging containers(97).

PLA was used for the production of plastic bags for household for bio

waste, barriers for sanitary products and diapers, planting cups, disposable

cups and plates(136).


14

1.5. Multilayer Packaging Films

Multi-layers films or laminates were produced to improve properties for

single bio-based polymers as well as co-extruded laminate films had become

increasingly important for many applications expecially in food industry

(packaging of fresh pasta, meats and cut vegetables) to extend the shelf-life

of the goods(118).

Biodegradable blends of PLA and poly-caprolacton (PCL) showed good

gas barrier properties(119) and a biodegradable hot-melt adhesive was

developed from PCL and soy protein isolate(120). Cups based on PLA and

PHB were used in protecting an orange juice simulant and a dressing from

quality changes during storages(121).

Multilayer films composed of a soy protein isolate inner layer and PLA

outer layer were prepared by a solvent casting method in order to investigate

the advantageous properties of both film materials. The lamination of PLA

layers on soy protein isolate (SPI) film resulted in desiderable gas barrier

properties with low water vapour permeability of PLA and low oxygen

permeability of SPI(122).

A biopolymer base sheet was laminated to a poly-glicolic acid resin layer

through a layer of a water based adhesive to form a multilayered sheet

characterized by excellent oxygen barrier properties and moisture not

permeability. The sheet was suitable for use as a packaging material base for

a food container(123). Sheets were also produced by corn starch, konjaku

starch, wax, oleic acid, zinc stereate, oleamide and PCL(124).

These materials were constructed by fusion/lamination of a biodegradable

resin layer on a base sheet of vegetable origin. This sheet had a lamination

structure made of a biodegradable material with light environmental burden

at disposal. It was excellent in oxygen-barrier properties, resistant to moisture

transmission and it was usable as a food container material(125).

Introduction

15

A biodegradable laminate was also reported for use in shaped paper based

articles (containers for liquid and solid, food products). Its substrate was

made of paper having first and second co-polyesters layers(126).

Laminates sheets comprising a core of higher melting PLA and a surface

layer of lower melting PLA were bonded together along the edge seemed to

give a sachet having a nozzle at the top seam of the sachet and it was suitable

for brewing coffee in the sachet. It was developed a new laminate films based

on modified starch and PLA characterized by good water and gas-barrier

properties.

Some laminates comprising a core coated with a PLA on the top side of

the core and a polyvinylalcohol (PVA) on the bottom side of the core were

developed. This material had good biodegradability, waterproofing, heat

sealing properties(124).

A biodegradable packaging material was used to indicate the expiration of

the shelf-life of the enclosed goods. The films was composed by a first film

layer, a second biodegradable film layer and a reactive chemical interposed

between the films. When the second layer was proximal to a food product,

reactive stimuli might include enzymes, bacteria, or chemicals emitted by the

food(125).

PLA based long fibre non-woven having mechanical properties,

biodegradability and heat-seal properties were suitable for use in a

biodegradable bag such as kitchen garbage bag or tea bag. The non-woven

fabric consisted of a lactic acid-based polymer and an aromatic polyester

copolymers(128).

Composite films from chitosan and PLA were prepared by a solution

mixing and a film casting procedure. The characterization of these blends,

based on bio-packaging for potential food applications, was evaluated and the

study of the antifungal activity of coatings and films on three mycotoxinogen

fungal strains was conducted. The hydrophobic nature of PLA reduced the


16

hydrophobicity of chitosan–based films and consequently improved their

moisture barrier properties and decreased overall the water/matrix

interactions(129).

1.6. Technology for Biobased Polymer Processing

The optimal processing for bio-based polymer, using in food packaging

applications, is based on the use of conventional apparatus that is normally

used in plastic factories.

By the way alternative technologies can be developed if the cost of the

variations in the production line is worthy of the results. Literature and

patents report studies on the trials to fit bio-based polymeric formulations for

the realisation of efficient food packaging suitable for pilot plant and

industrial scale productions.

There are many patents concerning the production of bio-films,

characterised by the arrangement of a flexible biodegradable polyester resin

(Ecoflex) between two kinds of PLA and co-extruding them through a die.

They showed an improvement in wrinkle, surface waviness, elongation

and impact resistance(130). A new material was composed of PLA or PLA

copolymer in the outer layer, producing by extrusion or coating

procedure(131).

A screening of a variety of food ingredients identified as pectin, pea

starch, gelatine/sodium alginate blends as potential materials for the

formation of stable edible films by estrusion with conventional extruders(132),

were selected.

Composite bio-films based on starch/PCL were composed by three–layer

PCL/starch/PCL sheets and they were prepared by a co-extrusion process(133).

There were some studies concerning the effects of biological factors on

the mechanical and morphological properties of plastics composites used for

Introduction

17

fermented food such as cottage cheese(134).

Biodegradable bags for food packaging comprised a laminate film

composed of a sealant layer made of a biodegradable polymer, a barrier layer

capable of blocking oxygen/vapour and a barrier layer-supporting that made

of a biodegradable polymer.

Bionolle 1001 film and an Al2O3/Lacty9800/paper laminated films were

dry-laminated using a biodegradable adhesive to give a film roll with a good

O2 and H2O permeability which was fabricated into a snack packaging bag at

a low heat-sealant temperature(135).

PhD Thesis-Arianna Barghini

Objectives

19

OBJECTIVES


20

In recent years, there has been an increasing trend towards more efficient

utilization of agro-industrial residues, such as sugar cane bagasse (SCB)(39)

and rice straw (RS). These natural fibers are gaining progressive account as

renewable, environmentally acceptable, and biodegradable starting material

for industrial applications, technical textiles, composites, pulp and paper,

civil engineering and building activities(141), as well as a source of chemicals

or building blocks(39).

Natural fibers offer a number of well-known advantages that include low

cost, availability of renewable natural resources and biodegradability(141).

Sugar cane bagasse (SCB) is a low value product burned for its energy

value(139) and rice straw (RS) has great potential as a lignocellulosic

feedstock for making renewable fuels and chemicals. However, RS appears

to be more recalcitrant than the other agricultural residues(137).

The disposal of rice straw by open-field burning frequently causes serious

air pollution, hence new economical technologies for the disposal of this

material and its utilization must be developed(140).

Applications of agro-industrial residues in pulping process and other

chemical production on the one hand provide alternative substrates, and help

in solving pollution problems, that their disposal may otherwise cause(39).

Waxes(51,138), found in rice straw and sugar cane bagasse, were removed

using a Kumagawa extractor with a solvent mixture toluene/ethanol (2:1 v/v)

to conduct the dewaxing process that was influenced by the particle size of

the agro-waste material.

The SCB recycling is based on the chemical modification of their

components, e.g. hemicellulose is used for producing xylitol, lignin for

producing phenolic resins, and cellulose for producing ethanol, composites,

and cellulose derivatives. The use of SCB for producing cellulose acetate

(CA) as well as membranes of this produced cellulose acetate was

proposed(13,46,145;153;148;150).

Objectives

21

Cellulose acetate (CA) is one of the oldest manmade macromolecule of

renewable origin(142),used extensively in the textile industry, filters,

photographic films, transparent and pigmented sheeting and plastic

compositions such as those used for compression, extrusion, injection

moulding and to a lesser extent, surface coating(48; 151).

This product was obtained by cellulose acetylation, in which cellulose

reacted with acetic anhydride that was used as acetylating agent, in the

presence of acetic acid as solvent, and sulfuric acid or perchloric acid used as

catalysts(13,154,144).

The CA degree of substitution (DS) can be defined as the number of acetyl

groups per anhydroglucose unit, and it can range from 0 for cellulose to 3 for

the triacetate. Higher-DS polymers are acetone-soluble and the CA polymers

with a DS below 1.7 do not dissolve in acetone. Moreover, there is a strong

link between the DS and the biodegradability; the lower the DS the more

biodegradable CA becomes which will make the lower-DS polymers very

important in CA copolymers and/or blends. Also, as the DS decreased, an

increase in the cristallinity was observed due to the fact that as the acetyl

content of low-DS decreased, a more "cellulose like", semi-crystalline

structure was adopted(48).

On the other hand, poly(hydroxybutyrate) (PHB) is one of the typical

natural bio-polyesters produced by many microorganisms as intracellular

carbon and energy storage compounds(156,146,143). PHB has attracted industrial

attention as an environmental friendly polymer for agricultural, marine, and

medical applications due to its biocompatibility and biodegradability(149;147).

However, it has several inherent deficiencies for use as a practical

polymer material, such as its brittleness due to high crystallinity and thermal

instability (Tm=180ºC).

To overcome the drawbacks of PHB and obtain some useful new material

properties, physical blending and chemical modification were adopted(32;155).


22

There were many attempts to blend PHB with other flexible polymers or

low molecular weight plasticizers to turn PHB into a material with improved

properties in impact strength, film formation, processing, mechanical

strength, amphiphilicity, biodegradability and biocompatibility(156,91,152).

In this regard, PHB was blended with the cellulose acetate (CA) obtained

from the cellulose acetilation with the aim to improve the application

properties of the polymeric material since the blending is a more convenient

and well-developed technology with lower cost for improving polymer

properties.

The second topic of this thesis analyses the production of

poly(hydroxyalkanoates) (PHAs) from olive oil mills wastewater, their

morphological, structural and thermal characterization and Lyfe Cycle

Assessment (LCA) evaluation.

PHAs can be obtained by the fermentation from several carbon source as

for example, sugar cane bagasse wastes in presence of the bacteria

Burkholderia Sacchari(17), and by surplus whey permeate from dairy

industries(18-20) from several bacterial strains such as Variovorax, Azeobacter

vinelandii, R. entropha and Haloferax mediterranei. This latter resulted more

economically efficient and ecologically feasible for the PHAs production.

The present LCA study performs a preliminary comparative evaluation of

the environmental impact associated to the production of PHAs according to

technology developed in the POLYVER Project(94). The obtained results

were compared to the values found in the relevant literature and they were

associated with the manufacture considering the PHAs produced with

technologies other than POLYVER and the oil derived commodity polymers

(such as PE, PP and PS) obtained by the traditional petrochemical

technologies.

The final objective of the POLYVER project was to develop and

implement a technology able to permit the conversion of OMW from a

Objectives

23

dangerous waste to a renewable source for biopolymers production. This aim

was accomplished by using OMW directly as the carbon source necessary for

PHAs accumulation.

The third topic was the production of blends based on biodegradable

polymers such as poly-lactic acid/Bionolle (PLA/Bn) and cellulose acetate-

poly (hydroxybutirate) (CA/PHB) to improve the plasticity and the

biodegradability of the polymers.

The fourth topic was the production of composites based on biodegradable

biomasses, such as algae, ground rice and its by-products.

Algae constitute a largely available, low value material from renewable

resource of marine origin to be used for the production of eco-compatible

composites. Fibers of the green alga Ulva armoricana, largely present on

French, Spanish and Italian costs, were evaluated for the production of hybrid

films with a hydrophilic, eco-compatible polymers, such as poly(hydroxy

butirrate) (PHB) and polycaprolacton (PCL), as continuous matrices(71) with

the aim to recycle this synthetic materials(68).

In a first screening of the material compatibility, PHB, PCL and Ulva

were utilized for the production of hybrid composites by compression

moulding. Positive results were obtained for composites forming properties

and mechanical characteristics attesting for Ulva suitability to be introduced

in industrial formulations, because of algal biomasses contain significant

amounts of crystalline cellulose as a structural component of the cell walls(68).

The aim was to make plastic items competitive with the conventional ones

that can be introduced in the market.

The latter topic was the background on the foaming agent and effervescent

materials with the aim to give new ideas for cleansings and drain cleaners

formulations.

Results

25

2. EXPERIMENTAL


26

The experimental chapter provides the chemicals and polymers used in the

formulation of composites and blends with biodegradable polymers and

fillers. The commercial products were used as received if not otherwise

stated.

2.1. MATERIALS

2.1.1. Reagents and Solvents

Hydrochloric acid, ethanol 96 %, sodium hydroxide were purchased from

Carlo Erba Chemical Co. (Italy). Sulphuric acid, hydrogen peroxide (30 %),

dichloromethane, chloroform, glacial acetic acid (99-100 %) were purchased

from J.T. Baker (The Netherlands). Toluene was supplied by BDH while

acetic anhydride was purchased from Sigma Aldrich.

2.1.2. Additives

Glycerol was kindly supplied by J.T. Baker (The Netherlands).

Magnesium stereate and pentaeritritol were purchased from Sigma

Aldrich; polyethylene wax and erucamide were kindly provided by Idroplax,

(Altopascio–LU-Italy).

2.1.3. Fillers

Organic fillers. Ulva (U) was supplied by Centre d’Etude et de

Valorisation des Algues (CEVA) (Pleubian-France); ground rice (FR) was

provided by Idroplax (Altopascio–LU- of Italy); chaff and flour were friendly

supplied by Canedole rice mill (Mantova). Sugar cane bagasse (SCB) and

rice straw (RS) were supplied by a sugar mill in Tanta (Egypt).

Results

27

Inorganic fillers. Calcium carbonate was supplied by Omya S.p.a

(Carrara-Italy); calcium sulphate was obtained from Tecno Boy (S. Piero a

Grado-Pisa-Italy). Zinc oxide was purchased from Tellerini S.p.a (Castel

Maggiore–Bologna-Italy); iron oxide was donated by Idroplax (Altopascio-

Lucca-Italy).

2.2. Polymers

BIOCYCLE® poly(3-hydroxybutyrate) (PHB), pellets with average

molecular weight (Mw)=425 kDa and polydispersivity (Mw/Mn)=2.51 and

microbially produced from Burkholderia Sacchari, was kindly supplied by

PHB Industrial S.A. (Brazil).

Poly(idroxyalkanoates) (PHAs) microbially produced from Pseudomonas

strain and Azotobacter sp were supplied by LABOR (Rome-Italy).

Poly(vinyl) alcohol (PVA) with hydrolysis degree 88 % and average

molecular weight (Mw)=67 kDa, was kindly provided by Erkol (Spagna).

Hydrolene LFT proprietary PVA formulations with various additives was

kindly supplied by Idroplax [Altopascio (Lucca)-Italy].

Wastes from hydrolene (LFT), containing inks and other products were

supplied by Idroplax [Altopascio (Lucca)-Italy].

Bionolle 1020 (succinate polybutylene) and Bionolle 1050 (polybutylene

adipate), pellets with –Mw-40-300 kDa and Mw/Mn in the range 1.8–4.5,

were obtained by Showa Highpolymer Co. (Japan).

Poly lactic acid (PLA), pellet –Mw-180 kDa, was supplied by Cargill Dow

LLC -Moël (Montelupo Fiorentino-Italy).

Poly caprolactone (PCL), grades CAPA 6500 and CAPA 6800 were

kindly provided by Solvay (UK). CAPA 6500 has a melt flow index (MFI) in

the range 6.3–7.9 and –Mw- 50 kDa. CAPA 6800 has –MFI- in the range

2.01-4.03 and –Mw- 80 kDa.


28

Scheme 2.1 depicts the chemical structure of various biodegradable

polymers PHB, PVA, PLA, Bionolle and PCL.

CHCH3

CH2 C On

CHCH2

CH2 Cm

CH3O O

O

(a) PHB (m=0)

(b) (c)

C O

O

CH2CH2 p q OC

O (c) p=2, q=4

(e)

Scheme 2.1. Structure of Polymers PHB (a), PVA (b), PLA (c), Bionolle (d)

and PCL (e).

Results

29

2.3. Polymers–Natural Fibres Composites

2.3.1 Preparation of PHB/Ulva Composites

Before melt processing, all materials were mixed physically and dried at

45°C in a laboratory oven under vacuum for 90 minutes.

Melt processing was performed in a torque rheometer W 50 EHT (with

roller blade) connected to a Plastograph Can-Bus Brabender at 170°C and 30

rpm by 7 minutes(1). Films were obtained by compression moulding in a

laboratory press at 180°C with a pressure of 90 bar by 6-8 minutes.

The composition and processing conditions for each formulation are

reported in Table 2.1. All single components were processed in the same

conditions for reference.

Table 2.1. Compositions and Processing Conditions of PHB/Ulva

Composites.

Formulation Melt mixing Compression moulding

T V Time T P Time

(°C) (rpm) (min) (°C) (bar) (min)

PHB 170 30 7 180 90 6-8

PHBU5 170 30 7 180 90 6-8

PHBU10 170 30 7 180 90 6-8

PHBU20 170 30 7 180 90 6-8

PHBU30 170 30 7 180 90 6-8

PHBU40 170 30 7 180 90 6-8

PHBU50 170 30 7 180 90 6-8

Before films preparation, the mixtures were dried at 45°C in a laboratory

oven under vacuum for 90 minutes. The composite PHB/Ulva (80/20) was


30

selected to perform an extrusion trial in a double screw extruder using a

sample of 850 g. and working conditions as reported in Table 2.2.

Table 2.2. Double Screw Extruder Working Parameters.

Sample T1 T2 T3 T4 Thead Speed

(°C) (°C) (°C) (°C) (°C) (rpm)

PHBU20 170 175 175 180 180 31.30

2.3.2 Preparation of PCL/Ulva Composites

PCL/Ulva composites composition and the working conditions are

presented in Table 2.3. Pristine PCL was also processed in the same

conditions as blank(2).

Table 2.3. Compositions and Working Conditions of PCL/Ulva

Composites.


T V Time T P Time


PCL 90 30 7 110 90 6-8

PCLU5 90 30 7 110 90 6-8

PCLU10 90 30 7 110 90 6-8

PCLU20 90 30 7 110 90 6-8

PCLU30 90 30 7 110 90 6-8

PCLU40 90 30 7 110 90 6-8

PCLU50 90 30 7 110 90 6-8

Results

31

2.3.3. Preparation of PHBPCL blends

PHB/PCL blends composition and the working conditions are presented in

Table 2.4. PHB and PCL were also processed in the same conditions as

blanks(2).

Table 2.4. Compositions and Working Conditions of PHBPCL Blends.


T V Time T P Time


PCL 170 30 9 180 90 6-8

PHB 170 30 9 180 90 6-8

PHB90PCL10 170 30 9 180 90 6-8

PHB80PCL20 170 30 9 180 90 6-8

PHB70PCL30 170 30 9 180 90 6-8

PHB50PCL50 170 30 9 180 90 6-8

PHB10PCL90 170 30 9 180 90 6-8

PHB20PCL80 170 30 9 180 90 6-8

PHB30PCL70 170 30 9 180 90 6-8


32

2.3.4 Preparation of PHBPCL/Ulva Composites

PHB/PCL/Ulva composites composition and the working conditions are

presented in Table 2.5.

Table 2.5. Compositions and Working Conditions of PHBPCL/Ulva

Composites.


T V Time T P Time


PHBPCL(80/20)U10 170 30 9 180 90 7-8

PHBPCL(80/20)U20 170 30 9 180 90 7-8

PHBPCL(80/20)U30 170 30 9 180 90 7-8

PHBPCL(80/20)U10 170 30 9 180 90 7-8

PHBPCL(80/20)U20 170 30 9 180 90 7-8

PHBPCL(80/20)U30 170 30 9 180 90 7-8

Results

33

2.3.5 Preparation of Hydrolene/Ground Rice Composites

Hydrolene/ground rice (LFTFR) composites composition and the working

parameters are presented in Table 2.6.

Table 2.6. Compositions and Working Conditions for Hydrolene/Ground

Rice Composites.


T V Time T P Time


LFT 190 30 7 180 90 6-8

LFTFR10 190 30 7 180 90 6-8

LFTFR20 190 30 7 180 90 6-8

LFTFR30 190 30 7 180 90 6-8

LFTFR40 190 30 7 180 90 6-8

LFTFR50 190 30 7 180 90 6-8

LFTFR60 190 30 7 180 90 6-8

The blends (300 g) LFTFR containing 30 % and 40 % of ground rice were

selected to conduct an extrusion in a double screw extruder using the working

conditions reported in Table 2.7.

Table 2.7. Double Screw Extruder Working Parameters.

Sample T1 T2 T3 T4 Thead Speed

(°C) (°C) (°C) (°C) (°C) (rpm)

LFTFR30 180 190 195 200 200 31.30

LFTFR40 180 190 195 200 200 31.30


34

2.3.6 Preparation of Hydrolene/Ground Rice/Calcium Carbonate

Composites.

Calcium carbonate was added in an increasing quantity (from 5 % up to 35

%) to the formulation LFTFR containing 40 % of ground rice.

Hydrolene/ground rice/calcium carbonate composites composition and the

working conditions are reported in Table 2.8.

Table 2.8. Compositions and Working Conditions of Hydrolene/Ground

Rice/CaCO3 Composites.


T V Time T P Time


LFTFR40 180 30 7 200 90 6-8

LFTFR40C5 180 30 7 200 90 6-8

LFTFR40C10 180 30 7 200 90 6-8

LFTFR40C15 180 30 7 200 90 6-8

LFTFR40C20 180 30 7 200 90 6-8

LFTFR40C25 180 30 7 200 90 6-8

LFTFR40C30 180 30 7 200 90 6-8

LFTFR40C35 180 30 7 200 90 6-8

Results

35

2.3.7 Preparation of Hydrolene/Ground Rice/Calcium Carbonate/

Calcium Sulphate Composites.

Calcium carbonate and calcium sulphate were added in the formulation

LFTFR40 in the percentages of 5 and 10 %. The amount of both inorganic

fillers in the formulation LFTFR30 was 15 %.

LFTFR40 was also processed in the same conditions as blank.

Composites composition and working parameters are reported in Table

2.9.

Table 2.9. Compositions and Working Parameters of Hydrolene/Ground

Rice/CaCO3/CaSO4 Composites.


T V Time T P Time


LFTFR40C5G5 180 30 7 210 90 6-8

LFTFR40C10G10 180 30 7 210 90 6-8

LFTFR40C15G15 180 30 7 210 90 6-8


36

2.3.8 Preparation of Hydrolene/Chaff and Flour Composites

Chaff and flour were mixed in the ratio 70/30, which was added to

hydrolene up to 40 %. LFT was also processed in the same conditions as

blank. Composites composition and working parameters are reported in Table

2.10.

Table 2.10. Compositions and Working Parameters of

Hydrolene/Chaff/Flour Composites.


T V Time T P Time


LFTPFc10 175 30 7 - - -

LFTPFc20 175 30 7 - - -

LFTPFc30 175 30 7 - - -

LFTPFc40 175 30 7 - - -

Results

37

2.3.9 Preparation of Hydrolene/PFc/Calcium Carbonate/Calcium

Sulphate Composites.

Composites composition and the working parameters are presented in

Table 2.11.

Table 2.11. Compositions and Working Parameters of

Hydrolene/PFc/CaCO3/CaSO4 Composites.


T V Time T P Time


LFTPFc20 175 30 7 175 80 7

LFTPFc20C5G5 175 30 7 175 80 7

LFTPFc20C10G10 175 30 7 175 80 7

LFTPFc20C15G15 175 30 7 175 80 7


38

2.3.10 Preparation of Poly(lactic acid)/Bionolle Blends

Composites composition and the working parameters are reported in Table

2.12.

Table 2.12. Compositions and Working Parameters of PLABn Blends.


T V Time T P Time


PLA 180 30 8 180 80 5-6

Bionolle 180 30 8 180 80 5-6

PLABn20 180 30 8 180 80 5-6

PLABn40 180 30 8 180 80 5-6

PLABn50 180 30 8 180 80 5-6

PLABn60 180 30 8 180 80 5-6

PLABn80 180 30 8 180 80 5-6

Results

39

2.4 Poly(hydroxyalkanoates) (PHAs) Extraction and Purification

2.4.1 PHAs Pretreatment

The aqueous biomasses deriving from a fermentation of oil wastes water

were centrifuged in a Rotofix 32A-1624 at speed 40x100 rpm for 30 minutes.

The sedimented materials were lyophilised and stored in a refrigerator at 4°C

for further purification and extraction.

The difference between purified and non purified biomass is shown in

Figure 2.1.

(a) (b)

Figure 2.1. Example of Non Purified (a) and Purified (b) Biomass.

2.4.2 PHAs Purification

Five grams of lyophilised biomass was mixed with 250 mL of acetone

and then stirred under reflux at 65°C for 12h under N2 atmosphere.

The solid biomass residue was filtered under vacuum with a Büchner

funnel and dried at room temperature in a desiccator.


40

2.4.3 PHAs Solvent Extraction

PHAs extraction was performed using a Kumagawa extractor under N2

atmosphere. About 5 grams of biomass was extracted in 250 mL of

chloroform under reflux for 7h at 55°C. Extracted PHAs solution was

concentrated using a rotary evaporator up to a volume of 20 mL.

These concentrated solution was dropped slowly into 100 mL of diethyl

ether at 0-4°C with constant strong stirring. Precipitated PHAs were filtered

and dried at room temperature.

2.5 Dewaxing of Ligno-Cellulosic Materials

2.5.1 Sugar Cane Bagasse (SCB)

Sugar cane bagasse was exposed to the open air to sunlight and then cut

into small pieces. The fibers were dried in an oven under vacuum at 55°C for

48h and finally grinded to fine powder with a blade grinder(5,8).

The powder was sieved and the fractions between the following mesh

sieves were collected: 0.60 mm- 0.425 mm; 0.425 mm- 0.3 mm; 0.212 mm-

0.15 mm; 0,15 mm- 0.106 mm; 0.106 mm- 0.053 mm.

Wax was removed from milled and chopped sugar cane bagasse (SCB) by

using a Kumagawa extractor (Figure 2.2). The solvent was a mixture of

toluene/ethanol (2:1). When the extraction was completed, dewaxed sugar

cane bagasse (DSCB) was dried under vacuum at room temperature

overnight. A sample of extracted solvent in the dean stark stopcock was taken

every three hours and evaporated using a rotavapor to check the progress of

extraction process and to dissolved wax (Scheme 2.2).

Results

41

Figure 2.2. Dewaxing of Sugar Cane Bagasse (SCB) Using a Kumagawa

Extractor (a) and Dewaxing Step-by-Step (b).

1

b)

2 3 4

56 78a)


42

Scheme 2.2. Dewaxing of Sugar Cane Bagasse (SCB).

2.5.2 Rice Straw (RS)

The rice straw (RS) was grossly dried by exposition open air to sunlight

and then cut to small pieces that were dried in an oven under vacuum at 55°C

for 48h and then pulverized with a blade grinder.

The chopped rice straw was sieved and the fractions between the

following mesh sieves were collected: 0.60 mm- 0.425 mm; 0.425 mm- 0.3

mm; 0.212 mm- 0.15 mm; 0,15 mm- 0.106 mm; 0.106 mm- 0.053 mm.

Wax was removed from rice straw (25 g) using a Kumagawa extractor in

which a mixture of toluene/ethanol (2:1) has been introduced.

A sample of extracted solvent in the dean stark stopcock was taken every

two hours and evaporated using rotavapor to check the progress of extraction

process.

Milled sugar cane bagasse

(Milled-SCB)

Dewaxed Sugar cane bagasse

(DSCB) Precipitated wax Dissolved wax

Sugar cane bagasse

(SCB)

Chopped sugar cane bagasse

(Chopped SCB)

Extracted solvent +

precipitate

Filtration

Milling

The solvent was evaporated using

rotavapor at 45-50°C.

Extraction with toluene/ethanol

(2:1, v/v) using KUMAGAWA for

9 hrs.

Results

43

After the extraction was completed, dewaxed rice straw (DRS) was dried

under vacuum at room temperature overnight.

The precipitate wax was filtered off and the filtrate was evaporated using

rotavapor to get the dissolved wax (Scheme 2.3).

Scheme 2.3. Dewaxing of Rice Straw (RS).

Milled rice straw (Milled-RS)

Dewaxed rice straw (DRS)

Precipitated wax Dissolved wax

Chopped rice straw (Chopped RS)

Extraction with Toluene/Ethanol (2:1, v/v)

using KUMAGAWA for 12 hrs.

Extracted solvent + precipitate

Filteration

Milling

The solvent was evaporated

using Rotavapor at 45-50°C.


44

2.6 Isolation of Water-Soluble Hemicellulose (WSH) Water-Soluble

Lignin (WSL)


The dewaxed sugar cane bagasse (DSCB) (10 g) was soaked in 300 mL

distilled water at 55°C for 2h with stirring as shown in Figure 2.3.

The water-soluble free residue (WSFR) was recovered by vacuum

filtration, washed with distilled water, and it was dried under vacuum at 50°C

for 48h.

The filtrate and supernatant were collected and concentrated on rotavapor

at 40°C to 30 mL. Water-soluble hemicellulose (WSH) was obtained by

precipitation of the concentrated aqueous extract in 4 volumes of 95 %

ethanol (120 mL) and the mixture was left with stirring at room temperature

for 1h. The precipitated water-soluble hemicellulose (WSH) was recovered

by filtration, was washed with 70 % ethanol and was air-dried.

After filtration, the filtrate and the supernatant were collected and were

acidified to pH 1.5, as adjusted by 6M HCl.

Water-soluble lignin (WSL) was obtained by evaporation on rotavapor till

dryness and it was freeze-dried (Scheme 2.4).

Results

45

Figure 2.3. Apparatus for the Sugar Cane Bagasse Dewaxing.


46

Scheme 2.4. Isolation of Water-Soluble Hemicelluose (WSH) and Water-

Soluble Lignin (WSL) from Dewaxed Sugar Cane Bagasse

(DSCB).

Precipitation in 120 mL of 95% ethanol

Pellet 1

Filtration

Dewaxed Sugar cane bagasse

(DSCB)

Filtrate Residue 1

Water-soluble free fraction

Pretreatment with distilled H2O at 55°C for 2h with stirring

Water-soluble Hemicellulose

(WSH)

Filtrate 1

Water-soluble Lignin (WSL)

Acidified with 6M HCl to pH 1.5

Concentrated to 30 mL on rotavapor at 40°C

Precipitate Filtrate

Evaporation on rotavapor at 40°C

Isolation of Cellulose and

Washed with 70% ethanol

and air dried

Results

47

2.7 Isolation of Cellulose, Alkaline-Peroxide-Soluble Hemicellulose

(APSH) and Alkaline-Peroxide-Soluble Lignin (ASL) from Water-

Soluble Free Dewaxed Sugar Cane Bagasse (WSFR)


Water-soluble free dewaxed sugar cane bagasse (WSFR) was dried under

vacuum at 50°C for 48h and soacked in the following solution: 20 g of 30 %

H2O2 was diluted to 300 mL with distilled water and the pH was adjusted to

11.5 with 4M NaOH.

The residue (cellulose) was recovered by vacuum filtration, it washed with

distilled water till neutral (pH 6-7) and it was dried under vacuum at 50°C for

48h.

The filtrate and the supernatant were collected and the pH adjusted to 5.5-

6 using 6M HCl. The filtrate was concentrated on rotavapor at 40°C to 200

mL.

Alkaline-peroxide-soluble hemicellulose (APSH) was obtained by

precipitation of the concentrated aqueous extract in 4 volumes of 95 %

ethanol (800 mL) and the mixture was left with stirring at room temperature

for 1h. The precipitated alkaline-peroxide-soluble hemicellulose (APSH) was

recovered by filtration, washed with 70 % ethanol and was air-dried.

After filtration, the filtrate and the supernatant were collected. Ethanol

was evaporated on rotavapor and then acidified to pH 1.0-1.5 using 6M HCl.

Alkaline-peroxide-soluble lignin (ASL) was obtained by evaporation of

water on rotavapor at 40°C till dryness and it was freeze-dried (Scheme 2.5).


48

Scheme 2.5. Isolation of Alkaline-Peroxide-Soluble Hemicellulose (APSH)

and Alkaline-Peroxide-Soluble Lignin (ASL) from Water-

Soluble Free Dewaxed Sugar Cane Bagasse (WSFR).

2.7.2 Rice Straw (RS)

Dewaxed rice straw (D-RS) was dried under vacuum at 50°C for 48h, then

2 % (w/v) H2O2 (pH 11.5) was prepared as previously.

Isolation of cellulose from D-RS takes place as in two steps as following:

the elimination of the organosolv-soluble fractions (OSH and OSL) was

performed soaking 10 g of DRS in 195 mL of a mixture of ethanol/distilled

water (2:1) and adding 5 mL of 0.2 N HCl, at 70°C for 4h with stirring.

Pellet 2

Filtration

Filtrate Residue 2

Treatment with 2% H2O2 (w/v) adjusted to pH 11.5

with 4M NaOH at 50°C for 16h with stirring

Alkaline peroxide-soluble Hemicellulose

(ASH)

Washed with 70% ethanol and air dried

Filtrate 2

Alkaline peroxide-soluble Lignin

(ASL)

Acidified with 6M HCl to pH 1.5

Cellulose

Washed with distilled water until neutral (pH

6-7) and dried at 50°C for 48 h.

Adjusted to pH 5.5 with 6M HCl

Concentrated to 30 mL on rotavapor at 40°C

Residue 1

(Water-soluble free fraction)

Results

49

The organosolv-soluble free residue (OSFR) was recovered by filtration

using a piece of cloth, washed with a mixture of ethanol/distilled water, and

was dried under vacuum at 50°C for 48h.

Alkaline-peroxide-soluble fractions, (APSH and ASL), were removed by

soaking the organosolv-soluble free dewaxed rice straw (9 g) in 300 mL of 2

% (w/v) H2O2 adjusted to pH 11.5 with 4M NaOH at 45°C for 16h with

stirring. The residue (cellulose) was recovered by vacuum filtration, washed

with distilled water till neutral pH and was dried under vacuum at 50°C for

48h.

2.8 PHB–Natural Fibers Blends

2.8.1 Acetylation of Cellulose

Acetylation of cellulose was carried out according to the following

procedure(9). Cellulose (3.0 g) was soaked in 75 mL of glacial acetic acid and

was stirred at room temperature for 30 min in a 250 mL round bottom-flask.

Then, 0.24 mL of conc. H2SO4 in 27 mL of glacial acetic acid was added

and stirring was continued for further 30 min at room temperature. Cellulose

pulp solution was separated by tilting the flask and pouring it into a beaker.

An amount of 96 mL of acetic anhydride was added to the solution, that

was poured back into the flask containing the cellulose. The reaction mixture

was stirred for 90 min and the flask was covered and left to stand at room

temperature for 17h. The reaction mixture was stirred at 30°C for 6h and then

was stood at room temperature for 16h.

The undissolved material was removed by filtration, and water was added

to the filtrate to stop the reaction and precipitate cellulose acetate (CA). The

produced cellulose acetate (CA) was filtered and washed with distilled water

till neutral pH acid and then dried at room temperature for 48h.


50

2.8.2 Production of Films by Casting

Cellulose acetate was dissolved in 5 mL of dichloromethane with stirring

for one week at room temperature (20°C), and PHB was dissolved in 5 mL of

chloroform by heating for 1h. The solution of cellulose acetate (CA) and

dichloromethane was added to that of PHB one and the mixture was stirred

for further 1-2h, to give a total concentration of 2.5 % in a mixture of

dichloromethane/chloroform (1:1). The solution was cast on a glass Petri dish

and the solvent was left evaporate.

After the evaporation of the solvent, the films were dried under vacuum at

room temperature till constant weight. Blends CA/PHB were produced in the

following amounts of CA: 20, 40, 60, 80, and 100 w/w, are referred as PHB,

PHB80, PHB60, PHB50, PHB40, PHB20, and CA, respectively(10,14).

2.9 Characterization of Building Blocks, Polymers and Relative Blends

and Composites

2.9.1 Thermogravimetric Analysis (TGA)

TGA experiments were performed in the thermogravimetric analyzer

Series Q500 of the TA Instruments. Generally, sample size was between 10-

20 mg. Two different range of temperatures were scanned at 10°C·min-1

under nitrogen atmosphere at 60 mL·min-1 flow rate. These range of

temperatures were from 30°C to 800°C and from 30°C to 600°C depending

on the type of filler (organic or inorganic) in the formulations, respectively.

Results

51

2.9.2 Differential Scanning Calorimetry (DSC)

A DSC instrument from Mettler-Toledo was used. a system consisting of

the DSC-822 module with FRS5 sensor and operated by means of STARe

software for making experiments and for the evaluation of the

thermodynamic parameters of polymers–natural fibres composites.

Samples of 5-10 mg were weighed in 40 µL aluminium pan and an empty

pan was used as reference. DSC temperature calibration was performed using

indium, lead and zinc standards and energy calibration by using indium

standard.

For the formulations containing poly(hydroxybutyrate),

poly(caprolactone) or hydrolene, the measurements were performed under

nitrogen flow rate of 80 mL·min-1 according to the following protocol:

1. First heating scan from 0°C to 210°C at 10°C·min-1 and 2 min of isotherm

at the end;

2. Cooling scan from 210°C to 0°C at 10°C·min-1;

3. Second heating scan from 0°C to 210°C at 10°C·min-1

For the formulations based on poly(lactic acid) and Bionolle, the

measurements were performed under nitrogen flow rate of 160 mL·min-1

according to the following protocol:

1. First heating scan from -50°C to 210°C at 10°C·min-1 and 2 min of

isotherm at the end;

2. Cooling scan from 210°C to -50°C at 10°C·min-1;

3. Second heating scan from -50°C to 210°C at 10°C·min-1.


52

For the formulations families containing ligno-cellulosic materials, the

measurements were performed under nitrogen flow rate of 160 mL·min-1

according to the following protocol:

1. First heating scan from 25°C to 200°C at 10°C·min-1 and 3 min of

isotherm at the end;

2. Cooling scan from 200°C to 25°C at 10°C·min-1;

3. Second heating scan from 25°C to 200°C at 10°C·min-1;

2.9.3 Scanning Electron Microscopy (SEM)

The cross-section morphologies of films were recorded using a JEOL

(JSM-5600LV) scanning electron microscope (SEM) at the required

magnification and with accelerating voltage of 14kV. The film samples

frozen in liquid nitrogen were fractured and sputtered with gold before SEM

observation.a

2.9.4 Wide Angle X-ray Scattering (WAXS)

Wide-angle X-ray diffraction patterns were performed at room

temperature with a Kristalloflex 810 diffractometer (SIEMENS) using a Cu

Kα (λ=1.5406 Å) as X-ray source. Scans were run in the high angle region

from 5° to 40° at scan rate of 0.016°/min and a dwell time of 1s.

a) SEM and WAXS were performed in the Department of Chemical Engineering, Industrial Chemistry and Materials Science, University of Pisa by Mr. Piero Narducci, to whom a grateful acknowledgement is described.

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53

2.9.5 Gel Permeation Chromatography (GPC)

GPC traces were performed using a Jasco PU-1580 HPLC liquid

chromatograph connected to Jasco 830-RI and Perkin-Elmer LC-75

spectrophotometric (λ=260 nm) detectors and equipped with two PLgel 5 µ

mixed-C columns (linear range of MW: 200-2,000,000) was used to obtain

average molecular weights. Chloroform stabilized with amylene was used as

eluent at 1.0 mL/min flow rate. The average molecular weight of the samples

were calculated using the calibration curve established from standard samples

of monodisperse polystyrene.

2.9.6 Transmission Fourier Transform Infrared Spectroscopy (FTIR)

Transmission infrared spectra of all samples were recorded with a Jasco

FT-IR Spectrometer mod. FT/IR-410 in the mid-IR region (4000-400 cm-1) at

4 cm-1 resolution using 32 scans. Samples were casted from CHCl3 solutions

on a KBr crystal plate.

2.9.7 Nuclear Magnetic Resonance (NMR)

1H-NMR spectra were obtained by means of a Varian Gemini VRX 200

(200 MHz) from deuterated chloroform (CDCl3) solutions.

2.9.8 Mechanical Tests

The tensile tests were performed on the specimens (ASTM D638)

according to the standard test method using a universal testing machine

Instron (model 5564) with a load cell of 2 kN and pneumatic grips.


54

Specimens were preconditioned inside desiccators containing saturated

solutions of magnesium nitrate (≈ 50 % RH) by 48h at 23°C (ASTM E104-

02)(14). At least 7 specimens for each sample formulation were tested and the

average value has been reported. A digital micrometer was used to monitor

film thickness. Measurements were performed with a crosshead speed set at

10 mm·min-1.

2.9.9 Fiber Analyzer

The instrument used for the determination of the chemical composition of

used lignocellulosic materials is a FIBER ANALYZER MOD. ANCOM

located in Department of Agronomy and Agrosystem Management (DAGA)

University of Pisa, Pisa, Italy.

The system is a pressure pot with a stirrer where the pouches similar to

tea-bags and made of synthetic material are immersed in a boiling solution

and stirred for 1h.

After that the solvent is unloaded and the sample is washed with distilled

water, acetone and dried in a ventilated oven. For the non dissolved fibres

(NDF) determination, α-amylase is used for eliminating starches. The sample

incineration is made by a muffola oven and the material is brought at

constant weight with an analytic balance.

2.9.10 Mill

Natural fibres and polymers were grinded using a grind Brabender Wiley

with a tri-phase motive power (0.75 keV), equipped with four static

mechanical shovels and six rotary ones. The mill has three interchangeable

sieves ((2 mm, 3 mm, and 4 mm).

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55

2.9.11 Brabender

The selected mixtures were worked using a torque rheometer Brabender

W 50 EHT (with a roller blade) connected with a Plastograph can-Bus-

Brabender.

2.9.12 Lab-Scale Double Screw Extruder

Materials granules were obtained mixing polymers and natural fibres in a

laboratory double screw (length=18L, D=2x25 mm), extruder (TEACH–

LINE ZK 25 T)-Collin.

2.9.13 Pilot-Scale Double Screw Extruder

The mixtures more promising were introduced in a double screw (D=20

mm) extruder (PRISM TSE 24 HC).

2.9.14 Compression Moulding

Compression moulding was performed using a press Collin P 200E

(D=196x196 mm, compression force ≤ 125 kN, hydraulic pressure ≤ 240 bar.

The plates have a maximum heating temperature around of 300°C

2.9.15 Density Measurements

Density measurements were performed using a picnometer(9).

A series of weights were performed: empty picnometer; picnometer+water

(32.52 g.), material+picnometer.


56

The difference in weight between the water with or without the material

represents the volume occupied by the material.

Results

57

3 RESULTS


58

The results chapter has been divided in six parts as indicated by

following:

1. Poly(hydroxyalkanoates) from olive oil mills wastewater:

characterization and LCA;

2. Modification of cellulose extracted from sugar cane bagasse (SCB)

and rice straw (RS);

3. Blends based on biodegradable polymers of natural and synthetic

origin;

4. Composites based on biodegradable materials and natural organic

fillers.

5. Background on the foaming agents

6. Background on the effervescent materials

3.1 Poly(hydroxyalkanoates) from Olive Oil Mills Wastewater:

Characterization and LCA

Poly(hydroxyalkanoates) are fully biodegradable polyesters of

hydroxyalkanoates (HAs) that are accumulated by several micro-

organisms(24).

Bacteria synthesize and accumulate PHAs as carbon and energy storage

materials or as a sink for redundant reducing power under the condition of

limiting nutrients in the presence of excess carbon source. When the supply

of the limiting nutrient is restored, the PHAs can be degraded by intracellular

depolymerases and subsequently metabolized as carbon and energy

source(15,16).

Once extracted from the cells, PHAs exhibit thermoplastic and elastomeric

properties. PHAs are recyclable, natural materials and they can be easily

degraded to carbon dioxide and water. They are excellent replacements for

petroleum-derived plastics in terms of processability, physical characteristics

and biodegradability. In addition, these polymers are biocompatible and they

Results

59

have several medical applications.

All of the monomeric units of PHAs are enantiomerically pure and in the

R-configuration. R-hydroxyalkanoic acids produced by the hydrolysis of

PHAs can also be widely used as chiral starting materials in fine chemical,

pharmaceutical and medical industries.

PHAs can be obtained by the fermentation of several carbon source as for

example, sugar cane bagasse wastes in presence of the bacteria Burkholderia

Sacchari(17), and by surplus whey permeate from dairy industries (18-20) from

several bacterial strains such as Variovorax, Azeobacter vinelandii, R.

entropha and Haloferax mediterranei. This latter resulted more economically

efficient and ecologically feasible for the PHAs production.

Finally PHAs can be extracted from bacterial strains that live in the olive

oil mills wastewater such as Pseudomonas and Azotobacter Sp, Azotobacter

Vinelandii and Azotobacter ChR(22), that were characterized in this study.

Tables 3.1 shows the identification codes and the preparation methods of

the samples produced using a Pilot Aerobic Reactor by Pseudomonas strain.

Table 3.1. Samples Produced by Pseudomonas Strain.

Sample Initial Quantity Final Quantity

(ml) (ml)

PAR-1 16000 16000

PAR-2 2000 1000

PAR-4 200 80

PAR-5 200 80

PAR-7 3000 2100

PAR-9 30 5a

PAR-10 370 15a

a) Quantity in grams.


60

The treatment for these samples consisted in a cooling at –80°C for 30

minutes for PAR-1, in an addition of Al2(SO4)3 for the precipitation for PAR-

2, in a biomass sedimentation, sampling, cooling at -80°C for 30 min and

sedimentation for PAR-4 and PAR-5.

The treatment for PAR-7 and PAR-9 was a biomass sedimentation to 10

lit, 10 lit of 3D water for washing followed by a biomass sedimentation to

approx 4 lit and a cooling at 80°C for 30 minutes, an addition of H2SO4 at

85°C for 40 minutes and the NaOH ones up to pH 10, the centrifugation at

10000 RPM x 15 min, a bleach solution 1:2 vol and a centrifugation after a

day.

Table 3.2 shows the identification codes and the preparation methods of

the samples produced using a small aerobic reactor by Azotobacter Sp.

Table 3.2. Samples Produced by Azotobacter Sp with a Small Aerobic

Reactor.


(ml) (ml)

SAR-1 500 50

SAR-2 100 100

SAR-3 100 100

SAR-4 100 100

The treatment for these samples was a cooling at –80°C for 30 minutes

followed by a biomass sedimentation using 6 g/l of Al2(SO4)3 and an

extraction with the HClO method.

Table 3.3 shows the identification codes and the preparation methods of the

samples produced using a pilot plant by Azotobacter Sp.

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61

Table 3.3. Samples produced by Azotobacter Sp with a Pilot Plant.


(lt) (ml)

PP-1 30 100

PP-2 1 50

PP-4 30 400

The treatment was a series of the same steps used for producing the SAR

samples.

Polyhydroxyalkanoates found a large number of applications in many

areas such as medicine, agriculture, tissue engineering, nanocomposites,

polymer blends and chiral synthesis(158).

The agricultural applications regards principally the production of mulch

films. In recent years Procter & Gamble have produced Nodax, that can be

used to manufacture biodegradable agricultural film. This material is a

copolymer containing mainly 3(HB) and small quantities of medium chain

length (MCL) monomers. It can degrade anaerobically and hence it can be

used as a coating for urea fertilizers to be used in rice fields or for herbicides

and insecticides.

Other applications of P(3HB-3HV) in agriculture concerned the controlled

release of insecticides and the bacterial inoculants used to enhance nitrogen

fixation in plants as confirmed by some experiments conducted in Mexico

using maize and wheat.

Increased and accelerated global economic activities over the past century

led to interlink problems that require urgent attention(188).

Greater emphasis was put on the concept of sustainable economic systems

that relied on technologies based on and supporting renewable sources of

energy and materials. Average UK households produce around 3.2 million


62

tonnes of packaging waste annually whereas 150 million tonnes of packaging

waste is generated annually by industries in the UK. The development of

biologically derived biodegradable polymers is one important element of the

new economic development.

3.1.1 Gel Permeation Cromatography

Typical GPC traces of PHAs produced by Pseudomonas strain,

Azotobacter Sp using a small aerobic reactor, Azotobacter Vinelandii and

Azotobacter ChR are shown in Figures 3.1-3.3.

The PAR-7 sample showed a monomodal (Fig.3.1). The weight average

molecular weight (Mw) of the sample was around 490 kDa with a

polydispersion index (Mw/Mn) of 5.15.

Figure 3.1 GPC Trace (RI detector) of PAR-7.

GPC traces of SAR-1, SAR-2, SAR-3 and SAR-4 samples are shown in

Figure 3.2. All sample solutions were prepared with the same concentration.

However, peak intensity between 11-16 min of elution time were very

different. Besides, that of samples SAR-1 and SAR-2 the signal was very

near to baseline. This was, probably due to the fermentation condition and/or

extraction method..

The values of Mw and Mw/Mn of SAR-3 and SAR-4 samples are reported

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63

in Table 3.4. The highest value of Mw was found in the case of SAR-4

sample (higher than 1000 kDa), that presented the lower Mw/Mn value too.

Peaks observed at higher retention time can be attributed to the presence

of oligomers and/or impurities.

Figure 3.2 GPC Traces of SAR-1, SAR-2, SAR-3 and SAR-4.

Table 3.4. Mw (kDa) of SAR-3 and SAR-4.a

Sample Mw Mw/Mn

(kDa)

SAR-3 714 3.74

SAR-4 1068 2.32 a) Mw is the weight average molecular weight; Mw/Mn is the polydispersity index.

GPC traces of 72h and 96h samples are shown in Figure 3.3. The first

sample was prepared by Azotobacter Vinelandii UWD as fermentation

microorganism and 60 % digested alperujo as culture medium for 72 hours

while the second one was prepared using Azotobacter ChR as fermentation

microorganism and 40 % digested alpeorujo as culture medium for 96 hours.

The values of Mw and Mw/Mn are reported in Table 3.5. The highest

value of Mw was found in the case of 96h (216 kDa) compared to 72h (188

kDa). Mw/Mn was basically the same for both samples and it was around 2.4.


64

Table 3.5. Mw (kDa) of 72h and 96h.

Sample Mw Mw/Mn

(kDa)

72h 188 2.37

96h 216 2.39 a) Mw is the weight average molecular weight; Mw/Mn is the polydispersity index.

Figure 3.3 GPC Traces of 72h and 96h.

3.1.2 Thermal Properties

Thermal characterization of polymers gave several important information

as for example degradation temperature (Td), processing temperature and the

miscibility between components of polymer blends and composites(7,23).

In the present study, thermal properties of PHAs were assessed by

thermogravimetry (TGA) and differential scanning calorimetry (DSC).

3.1.2.1 Thermogravimetry (TGA)

TGA provided important data parameters relating to thermal stability of

polymers(25). One of them was the decomposition temperature (Td), which

was defined as the onset temperature at the beginning of the weight loss. In

the present study, Td was defined as the temperature at 2 wt-% of weight loss.

Another parameter was the peak degradation temperature (Tp), which was

related to the reaction mechanism. The Tp data were obtained from the first

Results

65

derivate of TGA (DTGA) trace and they corresponded to the temperature at

the maximum degradation rate.

The experiments of this study were conducted under nitrogen atmosphere

in the range temperature of 25-500°C and the recovered residue was

measured at 500°C. The selected materials were the PHAs produced by

the bacterial strains in LABOR (Roma) facilities.

TGA data of PHAs produced by Pseudomonas strain using a Pilot Aerobic

Reactor are presented in Table 3.6.

The T2% values of PAR-1, PAR-2, PAR-4, PAR-5, PAR-7, PAR-9 were

235°C, 182°C, 151°C, 244°C, 239°C and 241°C, respectively. Tp2 value was

evident only for the PAR-2 sample; for the other samples it wasn’t possible

to determine this parameter, because of the ∆W2 was a shoulder of the main

degradation effect (∆W1).

Table 3.6. TGA Parameters in Nitrogen Atmosphere of PHAs Produced

by Pseudomonas Straina.

T2% Ton Tp1 Tp2 R500

Sample (°C) (°C) (°C) (°C) (wt-%)

PAR-1 235.4 242.3 264.9 - 2.4

PAR-2 182.3 235.9 260.8 328.42 8.8

PAR-4 151.3 221.9 244.1 - 4.0

PAR-5 244.7 256.6 279.7 - 1.5

PAR-7 239.5 242.6 272.9 - 0.4

PAR-9 241.8 248.3 264.9 - 1.5 a) T2% is the degradation temperature corresponding to 2% weight loss in the sample, ∆W is

the weight loss, Ton is the temperature corresponding to the beginning of the material

degradation, Tp is the temperature corresponding to the maximum weight loss rate, R500 is the

residual weight measured at 500°C.


66

TGA traces coming from thermogravimetric analysis (TGA) and their

corresponding DTGA ones of PAR samples under nitrogen flow are shown in

Figure 3.4.

(a) (b)

Figure 3.4 TGA (a) and DTGA (b) Traces Produced by Pseudomonas

Strain.

The first weight loss between 30°C-150°C probably was due to the

evaporation of some residual solvent used in the polymer purification.

The temperatures of maximum weight loss rate (Tp), corresponding to the

main weight loss step (∆W1), was observed in the range 260-280°C.

This step, which should correspond to polymer decomposition, can

provide an estimation of the real PHAs content in the samples and the

presence of impurity considering that pure PHAs didn’t leave residues after

pyrolysis. In particular, ∆W1 was calculated in around 96, 80 and 93 wt-% for

PAR-1, PAR-2 and PAR-7 respectively and 91 and 99 wt-% for PAR-4,

PAR-5 and PAR-9.

Values of T2% and Tp were in good agreement with the data commonly

reported in literature for PHAs(26-28). Another minor decomposition step

(∆W2) was observed at higher temperatures, calculated in around 2-9 wt-%.

Residual weight at 500°C (R500), was estimated in the range 0-9 wt-%.

These data indicated that PAR-2 (and partially PAR-1 and PAR-4)

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67

contained a relatively large amount of impurities that might derive from the

culture medium and not properly removed during the purification.

For the PHAs produced by Azotobacter sp using a Small Aerobic Reactor

(Fig. 3.5), the only T2% value was calculated only for SAR-4 sample.

Thermogravimetric data are presented in Table 3.7.


by Azotobacter Sp Using a Small Aerobic Reactora.

T2% Ton Tp1 R500

Sample (°C) (°C) (°C) (%)

SAR-1 - - - 89.5

SAR-2 - - - 91.2

SAR-3 - - - 72.4

SAR-4 180.1 210.6 241.0 7.1 a) T2% is the degradation temperature corresponding to 2% weight loss in the sample, ∆w is

the weight loss, Tp is the temperature corresponding to the maximum weight loss rate, R500 is

the residual weight measured at 500°C.

Figure 3.5 shows the TGA and DTGA traces for the SAR samples.

(a) (b)

Figure 3.5 TGA (a) and DTGA (b) Traces in Nitrogen Atmosphere of

Produced by Azotobacter Sp Using a Small Aerobic Reactor.


68

Samples SAR-1, SAR-2 and SAR-3 still contained an high amount of

impurities, as indicated by the high value of residual weight at 500°C (R500).

These values ranged from 91 wt% for SAR-2 to 72 wt-% for SAR-3. With

regard to SAR-4, the onset of thermal degradation, calculated as the initial 2

% weight loss (T2%) and the temperature of maximum weight loss rate (Tp)

were found at 180°C and 241°C respectively. The main weight loss step

(∆W1), which should provide an estimation of the real PHAs content in the

sample, was around 77.6 wt-%. Residual weight at 500°C was estimated in

around 7 wt-%.

In Table 3.8 are shown the data relative to the PP-1 sample, that is a PHA

produced by Azotobacter sp using a pilot plant and Figure 3.6 reports its

TGA (a) and DTGA (b) traces.


by Azotobacter Sp Using a Pilot Plant (PP-1)a.


Sample (°C) (°C) (°C) (°C) (wt-%)

PP-1 99.9 223.9 303.4 - 53.5 a) T2% is the degradation temperature corresponding to 2% weight loss in the sample, Ton is

the temperature corresponding to the beginning of the PHA degradation, ∆W is the weight

loss, Tp is the temperature corresponding to the maximum weight loss rate, R500 is the


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69

Figure 3.6 TGA and DTGA Traces of PP-1 Sample.

The onset temperature and the recovered residue at 500°C showed that PP-

1 sample presents an high quantity of impurities after purification.

TGA data of PHAs produced by Azotobacter Vinelandii and Azotobacter

ChR are reported in Table 3.9.


by Azotobacter Sp. at 72h and 96ha.


Sample (°C) (°C) (°C) (°C) (wt-%)

72h 211.0 263.5 295.5 325.1 3.6

96h 252.0 258.8 94.8 284.1 2.3 a) T2% is the degradation temperature corresponding to 2% weight loss in the sample, Ton is

the temperature corresponding to the beginning of the material degradation, ∆w is the weight

loss, Tp is the temperature corresponding to the maximum weight loss rate, R500 is the



70

Figure 3.7 shows TGA (a) and DTGA (b) traces for these two samples.

(a) (b)

Figure 3.7 TGA (a) and DTGA (b) Traces in Nitrogen Atmosphere of 72h

and 96h Samples.

T2% ranged from ca. 211°C (72h) to 252°C (96h), while the

temperatures of maximum weight loss rate (Tp), was observed in the range

285-295°C. On the other hand, the values of the main weight loss step ∆W1

(85-95 wt-%) and the residual weight at 500°C R500 (2-4 wt-%) indicated that

the polymers still contain impurities.

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71

3.1.2.2 Differential Scanning Calorimetry (DSC)

DSC analysis was performed in four scans. Figure 3.8 illustrates the

typical DSC trace of the PHAs produced by Pseudomonas strain using a pilot

plant reactor (a) and that of the PHAs produced by Azotobacter sp Vinelandii

and ChR (b).

(a) (b)

Figure 3.8 Second Heating DSC Traces of PAR-7 (a) and 72h-96h (b).

The thermodynamic parameters of PAR-7 are reported in Table 3.10. The

presence of a double melting peak at ca. 150°C and 163°C confirmed the

copolymeric nature of this sample. In fact, these values were typical of 3(HB)

copolymerized with 3-hydroxyvalerate 3(HV) units(26).

Table 3.10. Thermodynamic parameters of PAR-7 (second heating).a)

Tg ∆Hcc1 Tcc1 ∆Hcc2 Tcc2 ∆Ht Tm1 Tm2

(°C) (J/g) (°C) (J/g) (°C) (J/g) (°C) (°C)

PAR-7 0.4 50.9 52.7 21.6 62.2 24.3 150.5 163.3

a) Tg is the glass transition temperature, ∆Hcc is the cold crystallization enthalpy, Tcc is

the cold crystallization temperature, ∆Hm is the enthalpy of fusion, Tm is the melting

temperature.


72

3.1.3 FTIR Analysis

FT-IR spectra of PAR samples are reported in Figure 3.9.

The wavenumbers of the main PHAs FT-IR peaks reported in literature

are in Table 3.11. More relevant peaks were observed in the ranges 3400-

2850 cm-1 (CH3 and CH2 stretching) and 1500-1000 cm-1 (CH3 bending, CH2

wagging, C-O, C-C and C-O-C stretching), in addition to the very strong

carbonyl signal found around at 1724 cm-1.

Figure 3.9 FT-IR Spectra of PHAs Produced by Pseudomonas Strains..

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73

Table 3.11. Assignments of PHAs main FT-IR Absorption Bands(29-32).

Wavenumber (cm-1) Assignment

3437 OH stretching (H bridges)

2976 CH3 (asymmetric stretching)

2934 CH2 (asymmetric stretching)

2875 CH3 (symmetric stretching)

2855 CH2(symmetric stretching)

1724 C=O stretching

1453 CH3 (asymmetric bending)

1379 CH3 (symmetric bending)

1289 CH2 wagging

1278 CH2 wagging

1228 Conformational band of the helical chains

1184 C-O-C asymmetric stretching

1132 C-O-C symmetric stretching

1100 OH stretching

1057 C-O symmetric stretching

979 C-C stretching

929 CH2 rocking

896 CH3 rocking

825 CH3 rocking


74

FT-IR spectra of 72h and 96h are reported in Figure 3.10. Both polymers

showed the typical absorption peaks reported in Table 3.8, confirming that

they belong to the PHAs family.

Figure 3.10 FT-IR Spectra of PHAs Produced by Azotobacter Sp at 72h

and 96h.

3.2 LCA Evaluation for the PHAs Obtained from Wastewaters of Olive

Oil Mill

The goal of the present LCA study was to perform a preliminary

comparative evaluation of the environmental impact associated to the

production of PHAs according to technology developed in the POLYVER

Project(94).

The Functional Unit (FU) chosen in order to compare results from

different sources was 1 kg of polymer, and the LCA was based on a cradle-

to-factory gate approach.

Since POLYVER is still a technology under development, the two impact

categories that will be considered are Gross Energy Use (GEU) and Global

Warming Potential (GWP)(233,234).

These categories considered the relevant environmental impact regarding

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75

human health, plants and animals (ecological health), or the future

availability of natural resources (resource depletion).

In the work from Akiyama et al.(233), based on experimental results on lab

scale, the production of P(3HB-co-3HHx) and P(3HB) from the recombinant

strain of PHA-negative harboring the aeromonas cavie PHA synthase was

considered. The substrates were soybean oil for P(3HB-co-3HHx) and

glucose from corn for P(3HB). The reactor was a fed batch typo, with a

production rate 5000 tonnes per year. Fermentation step was accomplished

growing the cells in a mineral medium containing the substrate until nitrogen

is exhausted, followed by the production of PHA from the substrate in the

absence of nitrogen source. Assumed fermentation conditions were as

follows: fermenter volume: 300-750 m3, fermentation time: 30-50h, and

fermentation temperature: 34°C. The downstream process was accomplished

distruping the cells by sodium dodecylsulfate (SDS) pretreatment and

followed by sodium hypochlorite (NaOCl) washing, while PHAs were dried

by means of a spray dryer.

These experimental conditions leads to a cell concentration of 100-200 g/l

with a PHA content of 75-85 wt-%.

On the other hand, the report from Harding et al.(234) concerned the

production of P(3HB) starting from the experimental results obtained from

Harrison et al.(235) on a pilot plant scale using cupriavidus necator as

microorganism and sugar cane glucose as substrate. The reactor, operating at

30°C for 80h, was a fed batch type with a production rate of 1000 kg. In

particular, the sucrose feed was initiated after batch production of biomass,

and PHB started to accumulate with the onset of phosphate limitation.

After cell distruption, solid PHB was removed by centrifugation and re-

suspended with alkaline serine protease. Furthermore, PHB was treated with

non-ionic detergents and hydrogen peroxide (H2O2), both steps followed by

water dilution and centrifuge cycles. Finally, P(3HB) drying was performed


76

by means of a spray dryer. In these experimental conditions, cell

concentration of 150 g/l with a polymer content of 71 % was claimed.

Concerning relevant LCA issues, it was worth of notice that both studies

considered the carbon sources used for PHAs accumulation (soybean oil and

glucose from corn and sugar cane) as produced specifically for this purpose.

This was reflected in the fact that the whole environmental load due to

carbon source production was included in PHAs final impact. However, both

studies concluded that carbon sources production accounts only for a limited

share, and the processes contributing most to LCA impacts (Energy Use and

Global Warming Potential) were electricity and steam generation.

System boundaries of traditional and POLYVER technologies for PHAs

production and Olive Oil Mills Wastewater (OMW) are showed in Figures

3.11 and 3.12 respectively. Processes and Products were indicated with blue

and red colour respectively. Olive oil was assumed to be produced with a

three-phases process.

With the traditional technologies (Fig. 3.11), PHAs production and OMW

treatment belong to different process. From a general point of view, PHAs

production was typically composed of two different macro-steps: the

production of the carbon source followed by the polymer fermentation and

recovery. On the other hand, OMW was generated as by-product in olive oil

industry. Infact, the three phases milling technology, very common in Italy

and Greece but not in Spain, gave rise to three products: olive oil, olive husk

and OMW. On the other hand, OMW was found to be very rich of organic

matter (e.g. organic acids, lipids, alcohols and polyphenols), that increased its

phytotoxicity to very high levels. Due to this reasons, in order to reduce its

environmental impact, OMW had to treat with special techniques (e.g.

evaporation, physico-chemical treatments or biotechnological

transformations)(33,,34).

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77

Figure 3.11 System Boundaries of Traditional Technologies for PHAs


Figure 3.12 System Boundaries of POLYVER Technologies for PHAs


The final objective of the POLYVER project was to develop and

implement a technology able to permit the conversion of OMW from a

dangerous waste to a renewable source for biopolymers production. This aim


78

was accomplished by using OMW directly as the carbon source necessary for

PHAs accumulation. In this view, in comparison with the traditional one, in

the POLYVER scenario the two steps regarding the production of carbon

source and the treatment of OMW did not need to be performed anymore.

In order to render the two scenarios comparable, the System Expansion

method was applied. The system expansion approach (Fig. 3.13) broadened

the system boundaries and introduced a new functional unit to make the two

systems being compared equal in scope.

Figure 3.13 Schematization of System Expansion Approach.

For example, product A was produced by Process AB along with product

B. Product A was to be compared to product C which was the only product to

be produced by process C. Using system expansion, an alternative way to

produce product B was added to process C. The comparison now was

between Process AB and Process C plus Process D (34). Another approach to

applying system expansion was by subtracting the environmental burdens of

an alternative way of producing Product B so that only Product A was

compared to product C. This approach was also referred to as the “avoided

burden” approach since it was reasoned that the production of any alternative

products was no longer needed and the resultant environmental burdens were

avoided.

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79

The environmental burdens allocated to the product of interest were then

calculated as the burdens from the process minus the burdens of an

alternative co-product(34).

Since the output considered as FU was 1 kg of PHAs, this approach had

to be applied to the OMW management process, which can be treated in two

different ways: either added to PHAs impact in traditional technology or

subtracted from PHAs impact in POLYVER scenario. This second approach

was the one chosen for the present LCA. System Expansion was not applied

to the carbon source production since this step was just replaced by OMW

production in olive oil mills.

Data regarding the final yields of PHAs obtained by means of POLYVER

technology, in terms of biomass and polymer concentration in the culture

media, polymer content in the biomass and culture media needed for 1 kg of

PHAs are reported in Table 3.12.

Table 3.12. Biomass and Polymer Concentration in the Culture Media,

Polymer Content in the Biomass and Culture Media Needed

for 1 kg of PHAs.

Biomass Polymer Polymer Medium needed

Concentration Content Concentration for 1 kg PHAs

Sample (kg/m3) (%) (kg/m3) (l)

PAR-1 17.90 1.38 0.25 4050

PAR-2 11.90 0.44 0.05 19270

PAR-4 22.00 0.49 0.11 9340

PAR-5 10.00 0.18 0.02 56090

PAR-7 31.13 1.02 0.32 3160

PAR-9 12.25 24.07 2.95 340

Taking the culture media needed for 1kg of PHAs as representative factor,

the run that gave best yield results is PAR-9, with a value of 340 l/kg PHAs.


80

For this reason, the run PAR-9 will be taken as model to develop the

present LCA study. However, from a first comparison with the values listed

in Table 3.12, the yields obtained with POLYVER technology were much

lower than those reported in literature for other fermentation technologies.

Since OMW was used directly for PHAs production, it was assumed that

both olive oil mill and bioreactor were integrated in the same industrial plant.

In this way, no OMW transportation was required, leading to fuel savings.

As already illustrated, OMW was not produced specifically as PHAs

substrated, but it was generated as unwanted by-product in olives milling. In

this view, the impact arising from OMW production assumed to be

negligible. POLYVER process examined in detail was the purification and

extraction step. Input/output analysis of this step are schematized in Figure

3.14. The inputs related to this step were electricity and water consumption,

along with the utilization of acetone, chloroform and diethyl ether. On the

other hand, the three abovementioned solvents represented also the main

outputs.

Figure 3.14 Input/Output Analysis of PHAs Purification and Extraction.

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82

3.3 Conclusions

PHAs Produced by Pseudomonas Strain: From TGA analysis, purification

efficiency in the samples increased with the following order: PAR-9 > PAR-7

> PAR-1 > PAR-4 > PAR-2 > PAR-5. All polymers are most likely composed

by ca. 90 % of P(3HB) copolymerized with other HA units. This hypothesis

seems to be confirmed, in the case of PAR-7, from the double melting peak

detected by DSC. However, the molecular weight of PAR-7 was lower when

compared with PHAs produced with Small Aerobic Reactor.

PHAs Produced by Azotobacter Sp with Small Aerobic Reactor: Among

these samples, SAR-4 showed a relatively high value of molecular weight

(more than 1000 KDa). From TGA, SAR-4 was the sample containing less

impurities (ca. 7 wt-%). The residual weight of other 3 samples measured at

500°C ranged between 72 and 91 wt-%.

PHAs Produced by Azotobacter Sp with Pilot Plant: Among these

samples, PP-1 is the only sample that gave an available polymer

concentration (0.13 g/l). From TGA, PP-1 was the sample containing a large

quantities of impurities (ca. 53.5 wt-%).

PHAs from University of Granada: NMR and DSC indicated that both 72h

and 96h samples are almost fully composed of P(3HB) homopolymer. From

TGA 72h sample showed superior thermal performances, but also a higher

content of impurities. Molecular weight of 96h (216 KDa) was higher if

compared with 72h (188 KDa).

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3.4 Modification of Cellulose Extracted from Sugar Cane Bagasse (SCB)

and Rice Straw (RS).

Waxes is one of the most important lipophilic extractives found in rice

straw (RS) and sugar cane bagasse (SCB), in addition to fatty acids, sterols,

steryl esters, and triglycerides. These extractives when liberated during the

pulping process can cause significant problems for pulp and paper

manufactures as they are deposited as pitch, either alone or in combination

with fibers, fillers, defoaming agents, or coating binders. In recent years,

there has been an increasing trend towards more efficient utilization of agro-

industrial residues, such as RS and SCB. These natural fibers are gaining

progressive account as renewable, environmentally acceptable, and

biodegradable starting material for industrial applications, such as technical

textiles, composites, pulp and paper, civil engineering and building activities

as well as a source of chemicals or building blocks(39,45,141,162).

Extraction process of these two milled biomass was carried out using a

Kumagawa extractor and toluene-ethanol (2:1, v/v) as solvent mixture.

The obtained materials were characterized by thermal, morphological and

spectroscopic analyses.

So, the cellulosic fraction obtained from biomasses SCB and RS was

derivatized to obtain cellulose acetate (CA). The chemical procedure used

acetic anhydride (96 mL) as acetylating agent, in the presence of acetic acid

(27 mL) as solvent, and sulfuric acid (0.24 mL) as catalyst(39,45,162).

The past 10 years has witnessed a renewed interest in cellulose research

and application, sparked mostly by technological interests in renewable raw

materials and more environmentally friendly and sustainable resources.

The cellulose can be considered as a smart material using for biomimetic

sensor/actuator devices and micro-electromechanical systems. This smart

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cellulose is termed electroactive paper (EAPap). It can produce a large

bending displacement with low actuation voltage and low power

consumption. Because of cellulose EAPap is ultra-lightweight, inexpensive,

and biodegradable, it is advantageous for many applications such as micro-

insect robots, micro-flying objects, micro-electromechanical systems,

biosensors, and flexible electrical displays(237).

Cellulose acetate (CA) is one of the oldest man made macromolecules

used extensively in the textile industry, filters, etc. One of its applications is

the production of membranes for separation processes such as hemodialysis,

reverse osmosis and gas separation.

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3.4.1 Chemical Composition

Chemical composition of SCB as a function of treatment stage is reported

in Table 3.13.

Table 3.13. Chemical Composition (wt-%) of Egyptian Sugar Cane

Bagassea.

Sample wt-%

Extractive Moist Cel. Hecel. Lig Silica Ash

A B

C-SCB - 32 3.1 31.1 27.5 8.0 0.8 2.6

DC-SCB - - 2.7 42.1 33.2 9.5 1.1 2.5

M-SCB - 30 3.8 27.6 24.0 7.3 1.3 2.2

DM-SCB - - 2.1 39.8 32.2 13.3 1.9 2.8 a) A and B are water and toluene/ethanol (de-waxing) extractives, respectively; C-SCB and

DC-SCB are chopped and de-waxed chopped SCB, respectively; M-SCB and DM-SCB are

milled and de-waxed milled SCB pass 0.425 mm, respectively; Hcel, Cel, Lig and Si are

hemicellulose, cellulose, lignin and silica, respectively following van Soest procedure(@);

Moist determined gravimetrically

SCB as received (C-SCB) contained about 31 wt-% of cellulose, 27 wt-%

of hemicellulose and 8 wt-% of lignin. In general, these values decreased

slightly for the fraction of M-SCB and collected from the sieve that pass

0.425 mm (M-SCB). Exception was verified for the amount of silica.

The behaviour of the samples as received (C-SCB) and milled (M-SCB)

was some what different after de-waxing. Both samples presented higher

composition values of the components analyzed in relation to undewaxed

samples.

However, after milling only cellulose and hemicellulose decreased and the

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86

other components increased. Besides the samples that were milled and after

de-waxing (DM-SCB) resulted to have about 13 % of lignin that represented

an increasing of 62 % compared to C-SCB.

Chemical compositions as received, M-RS and DM-RS are reported in

Table 3.14.

Table 3.14. Chemical Composition (wt-%) of Egyptian Rice Strawa.

Sample wt-%

Extractive Moist Cel. Hcel. Lig Silica Ash

A B

C-RS - 9.4 3.3 29.7 12.6 12.7 10.7 15.1

DC-RS - - 4.9 39.6 15.4 7.0 12.3 15.2

M-RS - 8.1 1.9 31.6 14.7 7.0 10.5 15.0

DM-RS - - 4.4 31.2 15.9 12.4 12.4 15.3 a) A and B are water and toluene/ethanol (de-waxing) extractives, respectively; C-SCB and

DC-SCB are chopped and de-waxed chopped SCB, respectively; M-SCB and DM-SCB are

milled and de-waxed milled SCB pass 0.425 mm, respectively; Hcel, Cel, Lig and Si are

hemicellulose, cellulose, lignin and silica, respectively following van Soest procedure(@);

Moist determined gravimetrically.

The behaviour of RS as a function of milling and de-waxing was quite

different to that of SCB.

RS as received (C-RS) contained 30 wt-% of cellulose, 13 wt-% of

hemicellulose and 13 wt-% of lignin. After milling (M-RS), only moisture

and lignin decreased of about 42 % and 45 %, respectively compared to C-

RS. On the other hand, the values of cellulose and hemicellulose amounts

were higher than that of C-RS about 6 % and 17 %, respectively compared to

C-RS. This behaviour was contrary to that observed in M-SCB. As received

RS (DC-RS) after dewaxing showed to contain more amount of the

component analyzed except that of lignin in relation to C-RS. These changes

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87

corresponded to 48 %, 33 %, 22 %, 15 % increasing in moisture, cellulose,

hemicellulose and silica, respectively and 45 % decreasing in lignin.

However, for the composition of RS that was first milled (M-RS) and then

de-waxed (DM-RS) only moisture and lignin amount showed significant

changes with the treatment performed. These changes corresponded to an

increasing of 132 % and 77 %, respectively in compared to M-RS.

Both SCB and RS showed that ash amounts were basically invariable with

the milling and dewaxing treatments, which were around 3 % and 15 %

respectively. On the other hand, these biomass treatments had a significant

affect on their composition as previously showed.

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3.4.2 Morphology of Lignocellulosic Wastes

Comparative SEM photomicrographs of chopped (C), dewaxed-chopped

(DC), milled (M) and dewaxed-milled (DM) SCB and RS are presented in

Figures 3.15 and 3.16, respectively.

(a) (b)

(c) (d)

Figure 3.15 SEM Photomicrographs for M-SCB-35X (a), DM-SCB-37X

(b), C-SCB-43X (c), DC-SCB-35X (d).

Pictures c) and d) in Figures 3.15 and 3.16 showed the characteristic

cylinder and/or vascular bundles of the grass plants like straws and SCB.

These morphologies can also be observed in the water soluble free residue

(WSFR) resulted from the acetilation of cellulose obtained from SCB (Fig.

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89

3.17c). Moreover, the cellulose extracted from SCB (Fig. 3.17a) appeared as

an agglomerate of fibre and the cellulose acetate (CA) (Fig. 3.17b) from SCB

cellulose acetilation as a thick agglomerated powder.

(a) (b)

(c) (d)

Figure 3.16 SEM Photomicrographs for M-RS-100X (a), DM-RS-50X (b),

C-RS-220X (c), DC-RS-150X (d).

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90

(a) (b)

(c)

(c) Figure 3.17 SEM Photomicrographs for Cellulose from SCB-550X (a),

Cellulose Acetate-50X (b), WFSR-95X (c).

3.4.3 Thermal Properties of Lignocellulosic Materials

Thermal characterization of the two ligno-cellulosic based materials (SCB

and RS) and their derivative products gave informations on the degradation

temperature and the processability of the materials(36,39).

Thermal properties of SCB, RS and extracted cellulose were assessed by

thermogravimetry (TGA) and differential scanning calorimetry (DSC).

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3.4.3.1 Thermogravimetric Analysis (TGA)

TGA pyrolysis traces and their derivatives (DTGA) of as received (C-

SCB), milled (M-SCB) and dewaxed SCB (DM-SCB) are represented in

Figure 3.18 and their TGA data are in Table 3.15.

The weight loss steps observed in the samples C-SCB and M-SCB (Fig.

3.18) were at least six steps, where five of them were overlapped as shown

DTGA traces (Fig. 3.18b) that appeared as shoulder, peaks and tail. These

samples after dewaxing, DC-SCB and DM-SCB, presented three and two

weight loss steps, respectively.

The first step (25°C-120°C) of all samples corresponded to the moisture

volatilization and were 3.1 %, 2.1 %, 4 %, 4.7 % in the C-SCB, DC-SCB, M-

SCB, DM-SCB, respectively.

The second and third overlapped steps of weight loss in the samples C-

SCB and M-SCB occurred between ca 120°C and 240°C. These steps can be

assigned to the low molecular weight extractives, that in the case of SCB, can

be starch, sugars (principally saccarose), phenolics and tannins(157).

As the second step seemed to be a tail of the third one, the weight loss step

was calculated as a single step and corresponds to a 18.5 % and 20.1 % for C-

SCB and M-SCB, respectively.

This slight increasing on extractive amounts in the sample M-SCB

suggested that probably milling-sieving process concentrates something more

of fragile component in the fraction that pass 0.425 mm.

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(a) (b)

Figure 3.18 TGA (a) and DTGA (b) Traces of SCB Based Materials Under


Fourth weight loss step was measured between ca 240°C-300°C and the

values for C-SCB and M-SCB were 14.2 % and 18 %, respectively. The

principal chemical component of ligno-cellulosic biomass that decompose in

this range of temperature was the hemicellulose(41).

The highest amount of hemicellulose among C-SCB and M-SCB, from

chemical assessment (Table 3.13) was verified for the first one that

apparently disagreed with the TGA results. So, this meant that with milling-

sieving process changed the proportion between components, probably due to

the mechanical characteristics of each components as previously proposed.

The last weight loss step was a peak followed by a tail up to the end of the

experiment. The temperature range of the step corresponding to the DTGA

peak was between ca. 300°C-380°C, which principal component

decomposing was the cellulose. A small fraction of lignin that continue to

degrade at higher temperatures was present, too. The values of weight loss

for this step were 37 % and 35 % for C-SCB and M-SCB, respectively.

Finally in the temperature range of 400°C-800°C the weight loss was 6.6

% and 5.2 % leaving a recovered residue of 18.1 % and 15.3 % for C-SCB

and M-SCB, respectively. This last step corresponded principally to the

lignin decomposition and the residue to the inorganic materials and carbon.

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Table 3.15. Thermogravimetric Data of SCB Based Materials Under


Sample Ton Tp1 Tp2 Tp3 Tp4 Tp5 R800

(°C) (°C) (°C) (°C) (°C) (°C) (%)

DC-SCB 277 - 317 351 416 - 4.4

M-SCB 206 222 281 335 400 - 15.3

DM-SCB 275 - 306 352 447 - 19.6

C-SCB 221 220a 282 327 399 - 18.1 a) overlapped weight loss, b) shoulder.

C-SCB and M-SCB after extraction with the solvent mixture

toluene/ethanol (samples DC-SCB and DM-SCB, respectively) displayed no

weight loss steps in the temperature range of 120°C-240°C. So, C-SCB and

DM-SCB TGA traces suggested at least four weight loss steps, which the

first one corresponded to the moisture volatilization, as previously reported.

The first and second degradation weight loss steps in the temperature

range of ca. 200°C and 380°C were overlapped at around 320°C.

The values of these steps for DC-SCB were 30 % and 44 % and for DM-

SCB were 27 % and 44 %, respectively. The last step that resulted principally

from lignin pyrolysis corresponded to the weight loss in the temperature

range of 380°C-800°C that was ca. 8 % and corresponding to the DTGA peak

was 3 % for DC-SCB and DM-SCB, respectively. The residues recovered at

800°C were ca. 4 % and 20 %, respectively.

Table 3.15 records the TGA data of SCB based materials. The

temperatures of onset pyrolysis (Ton) depended on both milling-sieving

process and toluene/ethanol extraction. Ton value of C-SCB was 221°C, that

decreased of ca. 15°C after milling (M-SCB) and it increased ca. 56°C for the

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94

sample without extractives (DC-SCB).

On the other hand, both DC-SCB and DM-SCB presented equivalent Ton

values around 276°C. Consequently the difference in the thermal stability

among C-SCB and M-SCB was due to extractive composition.

The maximum rate of decomposition product volatilization (Tp) depended

principally from the toluene/ethanol extraction which values were higher than

that of pristine material.

TGA and DTGA experiments were conducted also under air atmosphere:

the traces and the relative data are presented in Figure 3.19 and in Table 3.16.

The samples C-SCB and M-SCB (Fig. 3.19) showed at least five steps,

while the same samples after dew axing process, DC-SCB and DM-SCB, had

four weight loss steps.

Under air atmosphere; the first step (25°C-120°C) of all samples

corresponded to the moisture and volatiles elimination and it was 2.3 %, 1.7

%, 1.6 %, 2.5 % in the C-SCB, DC-SCB, M-SCB, DM-SCB, respectively.

The second, the third and fourth steps of weight loss in the samples C-

SCB and M-SCB occurred between 120°C and 500°C. The third step for M-

SCB and the fourth one for C-SCB presented shoulders so as weight loss we

considered the total effect finding 18.1 % (M-SCB) and 30.3 % (C-SCB).

(a) (b)

Figure 3.19 TGA (a) and DTGA (b) Traces of M-SCB, C-SCB, DM-SCB,

and DC-SCB Under Air Atmosphere.

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For both samples, the second step felt down in the temperature range of

ca. 180°C-250°C and the corresponding weight losses were 12.5 % for C-

SCB and 19.9 % for M-SCB, respectively. The same trend was observed also

for the fourth step that occurred between 350°C and 500°C for C-SCB and

for M-SCB that corresponded to the weight losses of 30.3 % and 33 %,

respectively.

A difference in the intensity of these peaks was observed, because of the

milling process made the peak higher than the same one compared to the

pristine material.

Finally in the temperature range of 500°C-800°C the weight losses were

0.9 % and 22.4 % leaving a residue of 2.3 % and 4 % for C-SCB and M-

SCB, respectively.

Table 3.16. Thermogravimetric Data of SCB Based Materials Under Air

Atmosphere.


(°C) (°C) (°C) (°C) (°C) (°C) (%)

DC-SCB 265 - 295 322 437 469 2.9

M-SCB 203 222 292 321 445 - 4.0

DM-SCB 259 - 224 293 325 439 3.4

C-SCB 229 222 310 440 600 - 2.3

C-SCB and M-SCB after extraction with the solvent mixture

toluene/ethanol (samples DC-SCB and DM-SCB, respectively) displayed no

weight loss steps in the temperature range of 120°C-240°C.

So, C-SCB and DM-SCB TGA traces suggested at least four weight loss

steps, which the first one corresponded to the moisture and volatiles

elimination, as previously reported.

The shoulder in the first degradation weight loss step was more evident for

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96

DC-SCB respect to DM-SCB and the values were 37.5 % and 25.1 %,

respectively.

The weight losses for the real step were 32.8 % and 45.1 %. The same

effect was also evident in the second degradation weight loss step, mainly

due to the decomposition of cellulose and lignin. The values were 23.8 % for

DC-SCB and 21 % for DM-SCB. The residues recovered at 800°C were ca. 3

% and 3.4 %, respectively.

Table 3.16 reports the onset temperatures for the SCB based materials

before and after extraction when the TGA experiments were conducted under

air atmosphere.

The onset temperature for C-SCB was 229°C and it decreased of ca. 16°C

after milling (M-SCB) and it increased of ca. 36°C for the sample without

extraction (DC-SCB).

DC-SCB and DM-SCB had similar onset temperatures: the difference of

6°C suggested that the thermal stability depended on the extractive

composition.

Figure 3.20 reports the TGA (a) and DTGA (b) traces for RS before and

after milling and dew axing processes.

(a) (b)

Figure 3.20 TGA (a) and DTGA (b) Traces of M-RS, C-RS, DM-RS, and

DC-RS Under Nitrogen Atmosphere.

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97


volatilization and were 3.3 %, 3 %, 1.9 %, 4.4 % in the C-RS, DC-RS, M-RS,

DM-RS, respectively.

The second and third steps of weight loss in the samples C-RS and M-RS

occurred between ca 120°C and 240°C and the corresponding values were 4.7

% and 18.5 % for C-RS and 6.8 % and 46.7 % for M-RS. The residues

recovered at 800°C were ca. 31.8 % and 32.2 %, respectively.

The extraction process shifted the shoulder of the chopped material from

around 200°C to ca. 300°C and a third peak around at 480°C appeared in the

relative trace. The corresponding weight losses were 22.1 %, 34.2 %, 4.2 %

and the residue recovered at 800°C was 27 %.

In the DM-RS sample the shoulder was around at 190°C and it was

associated with a weight loss of 17.6 %. It was present only one degradation

weight loss step in the temperature range of 200°C-400°C, corresponding to

38.2 % of weight loss and a second effect smaller than the first one in the

temperature range 420°C-490°C with a weight loss of 4.6 %. The residue

recovered at 800°C was 29.5 %.

Table 3.17. Thermogravimetric Data for RS Based Materials Under



(°C) (°C) (°C) (°C) (°C) (°C) (%)

DC-RS 277 - 182 313 341 462 27.0

M-RS 259 - 325 466 568 - 32.2

DM-RS 272 - 124 324 468 - 29.5

C-RS 258 194 306 325 465 - 31.8

Table 3.17 shows the onset temperatures for the RS based materials.

RS before and after milling (C-RS and M-RS) processes had the same

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onset temperature, while this value increased of ca. 18°C for the sample after

extraction (DC-RS). So, also for RS, the extractive composition influenced

the thermal stability: the presence of wax, sugars, phenols made the material

less stable respect to the same one after the extraction process.

The TGA (a) and DTGA (b) traces for the RS based materials under air

atmosphere are reported in Figure 3.21 and the relative data are presented in

Table 3.18.

(a) (b)

Figure 3.21 TGA (a) and DTGA (b) Traces for RS Based Materials Under

Air Atmosphere.

Under air atmosphere, the weight loss steps observed in the samples C-RS

and M-RS (Fig. 3.21) were at least four, where two of them were overlapped

as shown DTGA traces (Fig. 3.21b).


and volatiles elimination and the relative weight losses were 3.3 %, 4.7 %,

3.9 % in the C-RS, M-RS, DM-RS, respectively.

The second step was a shoulder and it occurred in the temperature range of

120°C-240°C with a weight losses of 22.6 % for C-RS, 25.4 % for M-RS and

16.7 % for DM-RS. The third weight loss step occurred in the temperature

range of 240°C-365°C and principally it represented the cellulose

degradation.

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99

This material was associated with some sugars that started to degrade at

lower temperature respect to the same ones for the pure cellulose(160).

The weight losses were 29 % for C-RS, 25 % for M-RS and 41.3 % for

DM-RS.

The fourth step for C-RS felt down in the temperature range of 365°C-

500°C, corresponding to a weight loss of 24.6 %; the same material after

milling presented a degradation weight loss step of 8.8 %.

The residues recovered at 800°C were 15.9 % for C-RS and 28.9 % for M-

RS, respectively.

The DM-RS sample, under air atmosphere was degraded in four steps. The

first step with a weight loss of about 3.9 % that it occurred in the temperature

range of 25-100°C, represented the evolution of the moisture.

The shoulder with a weight loss of 16.7 % in the temperature range of

100-240°C, represented the extractives start decomposition of rice straw.

The third step with a weight loss of 41.3 %, represented mainly the

decomposition of cellulose. The fourth step, associated a weight loss of 22.5

%, principally represented the decomposition of hemicellulose and lignin.

The residue recovered at 800°C was 13.7 %.

Table 3.18. Thermogravimetric Data for RS Based Materials Under Air

Atmosphere.

Sample Ton Tp1 Tp2 Tp3 Tp4 Tp5 Tp6 Tp7 Tp8 R800

(°C) (°C) (°C) (°C) (°C) (°C) (°C) (°C) (°C) (%)

M-RS 264 193 323 468 - - - - - 28.9

DM-RS 258 293 405 609 - - - - - 13.7

C-RS 248 195 298 413 437 450 488 583 737 15.9

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Figure 3.22 shows the TGA (a) and DTGA (b) traces also for WSFR and

for the cellulose, while the relative data are in Table 3.19.

(a) (b)

Figure 3.22 TGA (a) and DTGA (b) Traces of SCB, DSCB, WSFR, and

Cellulose Under Nitrogen Atmosphere.

WSFR (Fig.3.22) was degraded in four steps. The first step with a weight

loss of about 1.2 % in the temperature range of 25-100°C represented the

evolution of the moisture, while the second step with a weight loss of 37.8 %

in the temperature range of 100-320°C represented probably the fraction of

hemicellulose after extraction of water soluble carbohydrates.

The third step with a weight loss of 41.2 % occurred in the temperature

range of 340-400°C and it represented mainly the decomposition of cellulose.

The fourth step with a weight loss of 4.2 % felt down in the temperature

range of 400-800°C, and it principally represented the decomposition of

cellulose and lignin. The residue recovered at 800°C was 11.4 %.

This material under air atmosphere, started to degrade at ca. 271°C with a

maximum weight loss step of 39.3 % in the temperature range 250-370°C.

The cellulose was less thermal stable because it was accompanied by some

sugars (pentosans) that degraded at lower temperature respect to the pristine

cellulose. The residue recovered at 800°C was 3.2 %.

From the TGA trace of cellulose (Fig. 3.22a), a slow weight loss from

room temperature up to 230°C was observed. This effect was attributed to the

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101

desorption of physically adsorbed water. Cellulose began to decompose at

298°C with a weight loss step of 66 %. The residue recovered at 800°C was

19.9 %.

Table 3.19. Thermogravimetric Data for Cellulose, D-SCB, SCB and

WSFR Under Nitrogen Atmosphere.


(°C) (°C) (°C) (°C) (°C) (°C) (%)

Cellulose 302 - 346 438 - - 19.9

D-SCB 277 - 317 351 - - 4.4

SCB 221 148 220 281 327 447 18.1

WSFR 277 - 315 366 - - 11.4

Figure 3.23 shows the TGA (a) and DTGA (b) trend for cellulose and

cellulose acetate (CA) under nitrogen atmosphere and the relative

thermogravimetric data are in Table 3.20..

(a) (b)

Figure 3.23 TGA (a) and DTGA (b) Traces of Cellulose, and Cellulose

Acetate (CA) Under Nitrogen Atmosphere.

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The cellulose acetate (CA) degraded in five steps. The first step

corresponded to the evaporation of the residual absorbed water and it

occurred in the temperature range of 25°C-120°C. The weight losses were 3.1

% for the cellulose and 2.8 % for the cellulose acetate (CA), respectively.

The second step presented a shoulder between 120°C-140°C, it

corresponded to the main thermal degradation of these materials and it

occurred in the temperature range of 140°C-240°C. The weight losses were 2

% for the shoulder and 27.1 % for the peak, respectively.

The third peak represented the totally decomposition of the materials and

the carbonization of the products to ash, that gave a weight loss step of ca. 66

% and it occurred in the temperature range of 240°C-420°C for cellulose

acetate.

The fourth step with a weight loss of ca. 48.5 % felt down in the

temperature range of 420°C-640°C and the residue recovered at 800°C was

11.4 %.

As we can observe from the same value for the onset temperatures in

Table 3.20, the two materials hadn’t the same thermal stability: the

acetylation process created important difference in the structure of these

materials.

Table 3.20. Thermogravimetric Data for Cellulose and Cellulose Acetate

(CA) Under Nitrogen Atmosphere.

Sample Ton Tp1 Tp2 Tp3 R800

(°C) (°C) (°C) (°C) (%)

Cellulose 298 - 345 442 19.6

CA 145 128a 184 355 11.4

a: shoulder

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Figure 3.24 shows the TGA (a) and DTGA (b) trend for cellulose and

cellulose acetate (CA) under air atmosphere, while Table 3.21 reports the

thermogravimetric data.

(a) (b)

Figure 3.24 TGA (a) and DTGA (b) Traces for Cellulose and Cellulose

Acetate (CA) Under Air Atmosphere.

The TGA trend (Fig. 3.24a) showed at least four degradation weight loss

steps for the cellulose and cellulose acetate. The first weight loss step

corresponded to the moisture and volatiles decomposition occurred in the

temperature range of 25°C-140°C. The weight losses were 3.1 % for

cellulose and 2.3 % for cellulose acetate, respectively.

The onset temperatures, as it has been shown in Table 3.21, were 300°C

for the cellulose and 160°C for the cellulose acetate: the acetylation process

made the cellulose derivative less thermal stable than the pristine material.

The second peak presented a shoulder that it occurred in the temperature

range of 220°C-240°C for cellulose and 120°C-140°C for cellulose acetate.

The shoulder corresponded to a weight loss of 67.4 % for cellulose and

27.9 % for cellulose acetate, respectively. For this latter material the second

peak corresponded to the thermal decomposition of hemicellulose and the

glycosidic links of cellulose(161).

The third weight loss step occurred in the temperature range of 240°C-

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390°C and it corresponded to weight losses of ca. 49.3 % for cellulose

acetate and 66 % for cellulose. It represented the thermal decomposition of

α-cellulose. The fourth step occurred in the temperature range of 460°C-

520°C for cellulose and 440°C-600°C for cellulose acetate, respectively.

The weight losses were 6.6 % for cellulose and 19 % for cellulose acetate

and they were associated principally with the lignin decomposition.

The residues recovered at 800°C were 19.9 % for cellulose and 0.35 %

for cellulose acetate respectively.

Table 3.21. Thermogravimetric Data for Cellulose and Cellulose Acetate

(CA) Under Air Atmosphere.

Sample Ton Tp1 Tp2 Tp3 Tp4 R800

(°C) (°C) (°C) (°C) (°C) (%)

Cellulose 298 - 345 442 - 19.9

CA 161 188 331 450 522 0.35

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105

The TGA (a) and DTGA (b) trend for alkaline-peroxide-soluble

hemicellulose (APSH) under nitrogen and air atmosphere are reported in

Figure 3.25, while the thermogravimetric data are in Table 3.22.

(a) (b)

Figure 3.25 TGA (a) and DTGA (b) Traces of Alkaline Peroxide Soluble


The first overlapped peak for the experiment conducted under nitrogen

and air corresponded to the moisture evolved in the temperature range of

25°C-160°C. The relative weight losses were 4.8 % in nitrogen and 4.9 % in

air, respectively.

The second DTGA peak (Fig. 3.35b) presented a shoulder for both

samples independently from the experiment atmosphere. This shoulder felt

down in the temperature range of 160°C-350°C and it corresponded to a

weight loss of ca. 45.9 % when the material was analyzed in nitrogen

atmosphere and 22.9 % when the same sample was analyzed in air

atmosphere.

The third peak occurred in the temperature range of 350°C-550°C for the

same sample in different conditions and it corresponded to a weight loss of

ca. 24.1 % for the APSH in nitrogen atmosphere and 33.9 % for APSH in air

atmosphere. The residues recovered at 800°C were 27.9 % and 12.9 % for

APSH under nitrogen and under air atmosphere, respectively.

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Table 3.22. Thermogravimetric Data for Alkaline Peroxide Soluble



(°C) (°C) (°C) (°C) (°C) (°C) (%)

APSHN2 222 165a 235a 288 444 537 27.9

APSHair 253 244 287 394 438 - 12.9

Table 3.22 reports the onset temperatures for the APSH under nitrogen

and air atmosphere. This value was around at 250°C for the APSH under air

atmosphere and it decreased of about 30 °C for the APSH under nitrogen one.

Figure 3.26 shows the TGA (a) and DTGA (b) traces for the alkaline-

peroxide-soluble lignin (ASL) under nitrogen and air atmosphere, while the

thermogravimetric data are in Table 3.23.

The ASL sample presented at least five weight loss steps in nitrogen

atmosphere and six ones in air atmosphere. The first step corresponding to

the moisture occurred in the temperature range of ca. 25°C-100°C and the

relative weight losses were 2.1 % under nitrogen and 3.8 % under air

atmosphere.

(a) (b)

Figure 3.26 TGA (a) and DTGA (b) Traces of Alkaline Soluble Lignin

(ASL) Under Nitrogen and Air Atmosphere.

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The shoulders of the main degradation peak occurred between 120°C and

290°C and they associated a weight loss of ca. 58.1 % for the TGA under

nitrogen atmosphere. For the same experiment under air atmosphere this

shoulder was comprised between 120°C and 220°C and the relative weight

loss was 32.5 %.

The main degradation peak was shifted for the ASL under air atmosphere

and it occurred in the temperature range of ca. 300°C-400°C in nitrogen

atmosphere, that became 300°C-550°C when the experiment conditions were

modified. The weight losses were 8.1 % for the first experiment and 55.1 %

for the second one. The fourth step occurred in the temperature range of ca.

550°C-600°C for both samples, corresponding to a weight losses of 6.8 % for

ASL under nitrogen and 3.1 % for ASL under air atmosphere.

Table 3.23. Thermogravimetric Data for Alkaline Soluble Lignin (ASL)

Under Nitrogen and Air Atmosphere.

Sample Ton Tp1 Tp2 Tp3 Tp4 Tp5 Tp6 R800

(°C) (°C) (°C) (°C) (°C) (°C) (°C) (%)

ASLN2 189 151 210 284 313 406 545 30.8

ASLair 177 151 208 264 360 462 580 1.9

The onset temperature didn’t change with the experiment conditions

(Table 3.23).

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3.4.3.2 Differential Scanning Calorimetry (DSC)

As shown by TGA analysis, the cellulose acetate (CA) started to degrade

around at 312°C so for the DSC measurements, the temperature range 25-

200°C was selected.

As we can see in the Figure 3.27, no peaks of fusion were evident in the

traces. In the DSC traces, the exothermic transitions were represented upward

following the International Confederation for Thermal Analysis (ICTA)

convenction. At the end to visualize the traces in the best manner the relative

offset were shifted from the zero point.

Figure 3.27 DSC Traces of Cellulose and Cellulose Acetate (CA) (Second

Heating).

Cerqueira et al.(55), gave a correlation between the enthalpy of fusion and

the cristallinity of the cellulose acetate (CA). The material started to degrade

around 300°C, so the process that they considered as a fusion is a degradative

process. Figure 3.28 shows the calorimetric traces for the SCB based

materials while Figure 3.29 shows the calorimetric traces for the RS ones.

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109

Figure 3.28 DSC Traces of M-SCB, C-SCB, DM-SCB, and DC-SCB

(Second Heating).

Figure 3.29 DSC Traces of M-RS, C-RS, DM-RS, and DC-RS (Second

Heating).

As shown in these Figures, in the temperature range 25-200°C no glass

transition temperatures are evident.

3.4.4 Infrared Spectroscopy (FTIR)

The FTIR spectra of M-SCB, DM-SCB, C-SCB, and DC-SCB are

reported in Figure 3.30(40;43;44;45,53). The FTIR spectrum of M-SCB (Fig. 3.30)

showed a strong band around 3379 cm-1 due to the stretching of the O-H

group, a weak band at 2924 cm-1 which attributed to the C-H stretching, band

at 1727 cm-1 which attributed to the stretching of the carbonyl group, bands at

1630 cm-1, 1603 cm-1, and 1430 cm-1 which attributed to the stretching of

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110

the benzene ring, bands at 1551-1510 cm-1 which attributed to the stretching

of the carbonyl group and keto group, band at 1372 cm-1 which attributed to

the -CH2- bending, a band at 1325 cm-1, and 1053 cm-1 which attributed to

the stretching of O-H, C-C, and C-O, and a band at 1246 cm-1 which

attributed to the stretching of the C-O-C of the pyranose skeletal.

The FTIR spectrum of DM-SCB showed a strong band around 3365 cm-1

due to the stretching of the O-H group, a weak band at 2897 cm-1 which

attributed to the C-H stretching, band at 1731 cm-1 which attributed to the

stretching of the carbonyl group, bands at 1632 cm-1, 1603 cm-1 , and 1426

cm-1 which attributed to the stretching of the benzene ring, bands at 1512 cm-

1 which attributed to the stretching of the carbonyl group and keto group,

band at 1374 cm-1 which attributed to the -CH2- bending, a band at 1327 cm-

1, and 1049 cm-1 which attributed to the stretching of O-H, C-C, and C-O, and

a band at 1246 cm-1 which attributed to the stretching of the C-O-C of the

pyranose skeletal.

(a) (b)

Figure 3.30 FTIR Spectra of M-SCB, C-SCB, DM-SCB, and DM-SCB (a)

and FTIR Spectra of SCB Before and After Dewaxing,

Cellulose, WFSR (b).

The FTIR spectrum of C-SCB (Fig. 3.30) showed a strong band around

3401 cm-1 due to the stretching of the O-H group, a weak band at 2920 cm-1

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111

which attributed to the C-H stretching, band at 1734 cm-1 which attributed to

the stretching of the carbonyl group, bands at 1637 cm-1, and 1490 cm-1

which attributed to the stretching of the benzene ring, bands at 1509 cm-1

which attributed to the stretching of the carbonyl group and keto group, band

at 1376 cm-1 which attributed to the -CH2- bending, a band at 1052 cm-1

which attributed to the stretching of O-H, C-C, and C-O, and a band at 1245

cm-1 which attributed to the stretching of the C-O-C of the pyranose skeletal.

The FTIR spectrum of DC-SCB showed a strong band around 3423 cm-1



stretching of the carbonyl group, bands at 1635 cm-1, and 1429 cm-1 which

attributed to the stretching of the benzene ring, bands at 1509 cm-1 which

attributed to the stretching of the carbonyl group and keto group, band at

1374 cm-1 which attributed to the -CH2- bending, a band at 1055 cm-1 which

attributed to the stretching of O-H, C-C, and C-O, and a band at 1253 cm-1

which attributed to the stretching of the C-O-C of the pyranose skeletal.

The FTIR spectrum of WSFR showed a strong band around 3403 cm-1 due

to the stretching of the O-H group, a weak band at 2904 cm-1 which attributed

to the C-H stretching, band at 1729 cm-1 which attributed to the stretching of

the carbonyl group, bands at 1601 cm-1, and 1428 cm-1 which attributed to the

stretching of the benzene ring, bands at 1509 cm-1 which attributed to the

stretching of the carbonyl group and keto group, band at 1373 cm-1 which

attributed to the -CH2- bending, a band at 1324 cm-1, and 1050 cm-1 which

attributed to the stretching of O-H, C-C, and C-O, and a band at 1248 cm-1

which attributed to the stretching of the C-O-C of the pyranose skeletal.

The FTIR spectrum of cellulose showed a strong band around 3429 cm-1



adsorbed water molecules, a band at 1429 cm-1 which attributed to the of the

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112

-CH2- bending, and a strong band at 1073 cm-1 which attributed to the

stretching of the C-O-C of the pyranose skeletal.

Figure 3.31 shows the FTIR spectra M-RS, DM-RS, C-RS, and DC-

RS,(40;43;44;45). The FTIR spectrum of M-RS showed a strong band around

3386 cm-1 due to the stretching of the O-H group, a weak band at 2924 cm-1

which attributed to the C-H stretching, bands at 1638 cm-1, and 1419 cm-1

which attributed to the stretching of the benzene ring, a band at 1057 cm-1

which attributed to the stretching of O-H, C-C, and C-O, and a band at 1205

cm-1 which attributed to the stretching of the C-O-C of the pyranose skeletal.

The FTIR spectrum of D-milled-RS showed a strong band around 3407

cm-1 due to the stretching of the O-H group, a weak band at 2925 cm-1 which


stretching of the benzene ring, band at 1510 cm-1 which attributed to the


attributed to the -CH2- bending, a band at 1058 cm-1 which attributed to the

stretching of O-H, C-C, and C-O, and a band at 1321 cm-1 which attributed to

the stretching of the C-O-C of the pyranose skeletal.

Figure 3.31 FTIR Spectra of M-RS, C-RS, DM-RS, and DC-RS.

The FTIR spectrum of C-RS showed a strong band around 3401 cm-1 due

to the stretching of the O-H group, a weak band at 2920 cm-1 which attributed

to the C-H stretching, band at 1734 cm-1 which attributed to the stretching of

the carbonyl group, bands at 1637 cm-1, and 1490 cm-1 which attributed to the

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113

stretching of the benzene ring, bands at 1509 cm-1 which attributed to the


attributed to the -CH2- bending, a band at 1052 cm-1 which attributed to the

stretching of O-H, C-C, and C-O, and a band at 1245 cm-1 which attributed to

the stretching of the C-O-C of the pyranose skeletal. The FTIR spectrum of

DC-RS showed a strong band around 3400 cm-1 due to the stretching of the

O-H group, a weak band at 2922 cm-1 which attributed to the C-H stretching,

band at 1645 cm-1 which attributed to the stretching of the carbonyl group, a

band at 1463 cm-1 which attributed to the stretching of the benzene ring, a

band at 1028 cm-1 which attributed to the stretching of O-H, C-C, and C-O.

The FTIR spectra of the cellulose, and cellulose acetate (CA) are reported

in Figure 3.32.

Figure 3.32 FTIR Spectra of Cellulose and Cellulose Acetate (CA).

The FTIR spectrum of CA showed a broad band around 3477 cm-1 due to

the stretching of the O-H group which decreased with cellulose acetate as a

result of esterification, compared to cellulose. Moreover for the cellulose

acetate, there were a new three bands at 1752 cm-1 which was assigned to the

C=O stretching vibration mode of the acetyl group, at 1378 cm-1 which was

assigned to the CH3 asymmetric bending vibration mode of the acetyl group,

and at 1237 cm-1 which was assigned to the C-O stretching vibration mode of

the acetyl group(46,47,53,54).

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114

The FTIR technique made the DS determination easier and faster than the

chemical titration method. The other problem with the titration method was

the fact that below a certain DP the method broke down and gave incorrect

results. Two peaks were of interest; the carbonyl group at 1751 cm-1 and the

hydroxyl group at 3464 cm-1. With the FTIR technique, the DS of any CA

polymer could be determined with the aid of the calibration curve.

The DS can be determined as the ratio of the hydroxyl peak height to the

carbonyl peak area in absorbance units(46,48,49).

Based on the ratio of hydroxyl peak height (0.094) to the carbonyl peak

area (36.413) with respect the calibration curve did by Samios et al.(48), it was

found that the degree of substitution (DS) to be 2.5.

Figure 3.33 shows the IR spectra for alkaline peroxide soluble

hemicellulose (APSH) (a) and alkaline peroxide soluble lignin (ASL) (b).

FTIR absorption frequencies of functional groups in the alkaline-peroxide-

soluble hemicellulose (APSH) and the FTIR absorption frequencies of

functional groups in the alkaline-peroxide-soluble lignin (ASL) are in Tables

3.24 and 3.25.

(a) (b)

Figure 3.33 FTIR Spectra of Alkaline Peroxide Soluble Hemicellulose

(APSH) (a) and Alkaline Peroxide Soluble Lignin (ASL) (b).

100

90

80

70

60

T (%

)

4000 3500 3000 2500 2000 1500 1000 500wavelenght (cm-1)

100

80

60

40

20

0

T (%

)

4000 3500 3000 2500 2000 1500 1000 500wavelenght (cm-1)

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115

Table 3.24. FTIR Absorption Frequencies of Functional Groups in the

Alkaline-Peroxide-Soluble Hemicellulose (APSH).

Functional Groups Wavenumbers (cm-1)

O-H stretching (Acid, Ethanol) 3426

C-H stretching (Alkyl, aliphatic) 2925

Absorbed water 1644

C-H bending 1416

O-H, C-C, C-O stretching 1332

C-O-C stretching (Pyranose ring skeletal) 1044

C-C stretching 785-466


Alkaline-Peroxide-Soluble Lignin (ASL).

Functional Groups Wavenumbers (cm-1)

O-H stretching (Acid, Ethanol) 3428

C-H stretching (Alkyl, aliphatic) 2940

C=O stretching (Carbonyl) 1700

C=C stretching (Aromatic skeletal mode) 1597

C=O stretching (Ketone and carbonyl) 1507

C=C stretching (Aromatic skeletal mode) 1422

C=C stretching (Aromatic skeletal vibrations) 1429

O-H, C-C, C-O stretching 1329

C-O-C stretching (Pyranose ring skeletal) 1228

Aromatic in plane deformation 1124

C-O stretching, C-O deformations (Ethanol) 1027

C-C stretching 834-526

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116

3.5 Conclusions

The ligno-cellulosic materials (SCB, RS) dewaxing process gave better

results for the milled sugar cane bagasse when compared with the cutted

material, depending on the strong increase of the superficial area due to the

milling process. The same process for rice straw did not produce the same

effect but only a saving time.

TGA experiments showed that the dewaxed material has an higher thermal

stability when compared with raw material.

This property was connected to the waxes amount, infact Ton showed an

increase from 206°C up to 275°C for the M-SCB and from 221°C up to

277°C for C-SCB in going from the pristine sample to the dewaxed one.

This reflects also a drastic residue decreasing (from 18 % up to 4.4 %) for

C-SCB before and after dewaxing.

The same trend for Ton and the residue was also confirmed for the SCB

analyses conducted under air atmosphere. The only exception was the slight

residue increase (from 2.3 % up to 2.9 %) for the DC-SCB. TGA analyses for

RS samples conducted under nitrogen and air atmosphere gave the same

informations.

Each component of both types of ligno-cellulosic materials was isolated

by some chemical methodologies and thermally characterized by TGA and

DSC experiments. Also the hemicellulose and lignin fractions soluble in

alkaline solutions showed an higher Ton when compared to that recovered by

TGA analysis performed under nitrogen atmosphere. The materials started to

degrade when some oxidative processes were just verified during their weight

loss steps.

The investigations on the chemical composition and structural features,

performed by Fiber Analyzer and SEM instruments, allowed for the

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117

determination of the percentage of each ligno-cellulosic component and for

confirmation of the agglomerated distribution of the cellulose fibers and their

acetylated products.

The FT-IR technique confirmed the structure of all SCB and RS samples,

the structure of each isolated fraction and permitted the determination of the

substitution degree for cellulose acetate considering the ratio of hydroxyl

peak height (0.09) to the carbonyl peak area (36.4) according to the

calibration curve.

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3.6 Blends Based on Biodegradable Polymers of Natural and Synthetic

Origin

Poly(lactic acid) is a condensation polymer of lactic acid, where lactic acid

is produced via fermentation from renewable resources. It is a biodegradable

polymer. PLA films were characterized for their tensile, thermal, gas

permeation (carbon dioxide, oxygen) and vapour barrier properties(57). The

choice of plasticizers varied depending on the intended application.

For example, in food packaging, considerations such as toxicity, migration

rates and miscibility are important determinations for creating a PLA

blend(58).

Many packaging examples are cited in the literature such as a biaxially

oriented surface-modified multilayered biodegradable polylactic acid film

prepared by co-extruding PLA with methylsilsesquioxanes as a core material

with a skin layer which is suitable for food packaging(59).

PLA films have better UV light barrier properties than polyethylene (PE)

but they are worse than those of cellophane, polystyrene (PS) and

poly(ethylenterephtalate) (PET). The vapour permeability coefficients of

PLA are lower than those of PS and higher than those of PET(60).

Nature Works PLA is suitable for food packaging applications and it can

be recycled back to monomers and polymers. It is fully compostable and it

breaks down like other biobased materials (Cargill Dow LLC. 04). Efforts to

recycle PLA would certainly provide an opportunity for its lower costs,

particularly in fresh food applications(61).

The effect of moisture sorption on the stability of PLA films under

variable humidity and temperature conditions was investigated by examining

the decrease in the number average molecular weight (Mn) and the loss of

their tensile strength in films. Generally, PLA is mechanically stable over a

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119

wide range of humidity (dry to moist) and temperature (chilled to ambient

temperature)(62).

The mechanical behaviour of various types of biodegradable materials

depends, mainly, on their chemical composition, as well as application and

storage conditions(164).

Various additives are incorporated in PLA formulations to improve

functionality of bio-blends. Sometimes these additives in formulations could

ever reach the levels of the conventional plastics.

It is well known that the environmental conditions during production,

storage, and usage of these materials influence their mechanical properties.

Ageing during the useful lifetime also causes great losses in the

elongation.

Briassoulis et al.(164) analyzed the overall mechanical behaviour of

biodegradable films based on starch, PHB, PLA and PCL-starch, that may be

considered suitable for agricultural applications, but also of partially

biodegradable films.

Selected critical mechanical properties of films prior to their exposure to

biodegradation were investigated and compared against those of conventional

agricultural films.

Three major commercially available biobased degradable polymers groups

were utilized to produce biodegradable films. These included, starch,

polyhydroxybutyrate (PHB) and polylactides (PLA).

The non biobased biodegradable polymers included polyesters derived

from petrochemical feedstock. Commercial films were developed from bio-

copolyesters (e.g., Eastar) or from starch-PCL blends(165).

Other biodegradable materials were also used for film production (e.g.,

blends of soy protein and biodegradable polyesters, etc.)(165).

Photo-biodegradable polyethylene (PBD-PE) films containing starch were

developed and used in agriculture(189). They were better able to raise

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120

temperature, preserve moisture, and increase crop yields, compared to

conventional polyethylene films. They also had advantage over their

synthetic counterpart in that they are environmentally degradable after their

useful life is over.

Because of their low production cost, good physical properties, and light

weight, many useful products were developed from these plastic blends for

use in many fields, including agriculture. Particularly, the polyethylene (PE)

mulch films were in use for many years to improve crop yields. One

drawback for the PE films is that they don’t degrade in soil and accumulates

thus, have to be removed after their use which adds to the overall cost for

farmers.

The waste films if left uncovered, pollute the soil and impacts the growth

of crops the following year. To overcome this problem, alternate films

techniques were developed in recent years but most of them were either

produced at a much higher cost or exhibited poor degradability in soil.. A

good option appeared to be the photo biodegradable polyethylene (PBD-PE)

film whose physical and mechanical properties were close to those of PE

films and also biodegradable in soil. Such films are commercially available at

very low cost and show good time-controlled environmental degradability.

There have been a lot of reports on preparation, properties, and

applications of degradable polymeric materials, but only few reports are

available with respect to their agricultural application.

Wang et al.(189) reported some preliminary results on the effects of the

agricultural application and the environmental degradation of the PBD-PE

film.

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121

3.6.1 PLABn Blends

3.6.1.1 Thermal Properties

Thermal characterization of the two pristine polymeric materials and their

blends provided informations on the degradation temperature and the

processability(68,69). Thermal properties of PLA, Bionolle (Bn) and PLABn

blends were assessed by thermogravimetry (TGA) and differential scanning

calorimetry (DSC).

3.6.1.1.1 Thermogravimetric Analysis (TGA)

Figure 3.34 shows the weight loss and the derivative weight loss traces

of PLA before and after melt processing. Table 3.26 provides informations

on the thermal properties for the PLABn blends. The onset temperature was

comprised between 310°C and 350°C.

Table 3.26 Thermogravimetric Data for PLABn Blends Under Nitrogen

Atmospherea.

Sample Ton Tp1 Tp2 R800

(°C) (°C) (°C) (%)

PLA 332 364 - 0.98

Bn 353 395 - 2.04

PLABn20 343 373 393 0.95

PLABn40 324 355 381 1.54

PLABn50 314 346 380 1.53

PLABn60 338 367 397 1.63

PLABn80 339 336 393 1.61

a) Ton is the starting degradation temperature, Tp is the main degradation peak, R800 is the

residue at 800°C.

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122

Both pristine and melt processing PLA exhibited similar thermal

behaviour. The onset temperature of decomposition in N2 atmosphere was ca.

302°C and the residue recovered at 600°C were ca. 1.47 %.

Figure 3.34 shows the weight loss (a) and the derivative weight loss (b)

decomposition traces for PLABn blends compared to pristine PLA and Bn.

(a) (b)

Figure 3.34 TGA (a) and DTGA (b) Traces for PLABn Blends.

All the blends started to degrade in the temperature range of 25°C–310°C

corresponding to the moisture volatilization and the weight loss steps of 0.36

%, 0.45 %, 0.56 %, 0.61 %, 0.48 %, for blends with Bionolle percentage

increasing from 20 % to 80 %, respectively.

The first decomposition DTGA peak appeared when the Bionolle

percentage raised to 40 % and it diminished progressively in the temperature

range of 350°C–390°C.

A shoulder was apparent at the first weight loss in PLABn blends with

compositions 40/60 and 20/80 which were mainly from the PLA

decomposition. The relative weight losses were 87.2 % for PLABn20, 24.9 %

for PLABn40, 56.4 % for PLABn60 and 17.3 % for PLABn80, respectively.

In the compositions 80/20 and 60/40, the main peaks in the temperature

range of 360°C-400°C exhibited a shoulder at high temperature, ca 392°C.

The relative weight loss steps were 10.7 % for PLABn20 and 41.9 % for

PLABn40. On the other hand, the shoulder appeared on the low temperature

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123

side of the peak in the temperature range of 300°C-360°C for the composition

40/60 and 20/80. The relative weight loss steps were 41.1 % for PLABn60

and 17.3 % for PLABn80. In the temperature range of 340°C-440°C both

blends showed a principal peak with a weight loss steps of 56.4 % and 79.7

% for PLABn60 and PLABn80, respectively.

The residue recovered at 800°C was 1.5 % but increased with increasing

amount of Bn in the blend.

The derivative TGA traces (Fig. 3.34b) showed an overlapped peaks for

the formulation PLABn50 and the relative weight loss steps in the

temperature range of 280°C-430°C were 51.6 % and 44.1 %.

With 50 % Bionolle present in blends, the thermal stability decreased for

pristine PLA (Ton=332°C) to the blend PLABn20 (Ton=314°C), whereas for

the percentages higher than 50 % for Bionolle, the thermal stability increased

up to 340°C in PLABn80.

The Bionolle appeared to be a poor plasticizing agent for the pristine PLA.

Infact, the blends with an high Bionolle contents had the same onset

temperature as the pristine PLA.

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124

3.6.1.1.2 Differential Scanning Calorimetry (DSC)

Figure 3.35 shows the DSC traces for the PLABn blends while Table 3.27

shows the relative thermodynamic properties.

Figure 3.35 DSC Traces for PLABn Blends (2nd Heating).

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125

Table 3.27 Thermodynamic Properties for PLABn Blendsa (2nd Heating).

Sample Tg Tcc1 Tm1 ∆Hm1 Tcc2 Tm2 ∆Hm2 Tm3 ∆Hm3

(°C) (°C) (°C) (J/g) (°C) (°C) (J/g) (°C) (J/g)

PLA 61 - - - ±130 153 13.58 - -

Bionolle -21 ±105 113 61.63 115 - - -

PLABn20 59 - 111 7.19 118 150 22.15 154 6.07

PLABn40 59 ±100 112 20.91 120 151 19.34 154 6.04

PLABn50 61 ±100 116 24.43 115 154 10.82 159 5.48

PLABn60 57 ±100 113 34.13 - 152 9.77 155 1.9

PLABn80 56 ±100 112 50.28 - 148 3.12 155 3.49

a) Tg = glass transition temperature, Tcc = cold crystallization temperature, Tm = melting

temperature, ∆Hm = melting heating.

The DSC traces of the blends showed a serie of peaks that correlated well

the cold crystallization and melting processes.

The PLABn blends showed the melting peaks where the low and high

transitions corresponded to Bionolle and PLA, respectively.

The high mobility of Bionolle chains plasticized only slightly the chains in

PLA, decreasing the glass transition temperature (Tg) from 61°C to 56°C for

the blend PLABn80 that contained the highest fraction of Bionolle

(Tg=25°C).

The 50/50 blend of PLA and Bionolle had the same Tg as neat PLA.

All blends exhibited cold crystallization temperature (Tcc) for both

polymer phases, which was followed by the corresponding melt transition.

It occurred around 128°C for the pure PLA and with an enthalpy value of

ca. 13 Jg-1.

The melting temperature ranged between 150°C-160°C respective of the

weight ratio of PLABn in the blends.

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126

The melting temperatures for Bionolle and PLA were 113°C and 153°C,

respectively. The Tm of Bionolle decreased for all compositions containing

less than 50 % PLA no change was observed with higher amounts of

Bionolle present in the blend. On the other hand, the melting transition of

PLA in the blends indicated two peaks. The first peak decreased from 150°C

to 148°C with increased amount of Bionolle; exception was observed in

blends containing only 50 % Bionolle.

The second melting peak of PLA in the blend was roughly 2°C higher than

that of the pristine polymer and was irrespective the amount of PLA present

in the formulation.

The peak intensity depended very much on the amount of the two polymeric

materials present in the blend. Infact, increased Bionolle contents led to

increase the cold crystallization peak that showed a decrease for PLA.

3.6.1.2 Mechanical Properties

The mechanical properties of PLABn blends are presented in Figure 3.36.

Substantially, significant changes were observed in blends with respect to

their Young modulus (YM) and the elongation at break (EL).

YM value for neat PLA and unblended Bionolle are 225.6 MPa and 622

MPa, respectively.

The YM of the blends increased progressively with an increasing amount

of Bn in the blend up to around 50 % approximately YM of 135 MPa.

Thereafter, any further increase in Bn content adversely impacted the YM

of the blend.

The elongation at break, never decreased generally with increase in Bn

content the only exception was a single peak at 20 % Bn content.

Results

127

Figure 3.36 Graphic of the Mechanical Properties of PLABn Blends.

Wool(238) analyzed the preparation methods of triglycerides with acrylate

functionality from various oils and model triglycerides.

The triglyceride-acrylates were homopolymerized and copolymerized with

styrene. Although the model predictions overestimated the cross-link density,

the trends in the cross-link density predictions matched the experimental

results. In both cases, the cross-link density was found to increase gradually

at low levels of acrylation and then linearly at higher levels of acrylation.

The deviation in the experimental results and model predictions were

obtained from intramolecular cross-linking. Approximately 0.5 and 0.8

acrylates per triglyceride were lost to intramolecular cyclization for

homopolymerized triglyceride-acrylates and triglycerides copolymerized with

styrene, respectively.

Their tensile strength and modulus increased exponentially at low levels of

acrylate functionality, but increased linearly at higher levels of acrylate

functionality, as predicted by vector percolation theory.

The cross-link density is a function of the number of functional groups so

the mechanical properties of triglyceride-based polymers were strong

functions of the number of acrylates per triglyceride. As this property

increased, the polymer chains became more tightly bound to each other,

which increased this properties. This was indicative of a percolation

phenomenon(239,240), that is a theory where the polymer properties are

Results

128

correlated to the connectivity of the polymer network. So the crack in the

polymer can travel through regions of much lower cross-link density and

stiffness than the average across the whole polymer.

Something similar happens for the PLA/Bn blends containing a Bn

amount up to 20 %: until this percent weight ratio, the obtained blends appear

to be good for the mechanical properties, because there are strong

interactions between the two biodegradable polymers such as hydrogen

bounding or between carboxylic groups.

Results

129

3.6.2 PHB/Cellulose Acetate (CA)

3.6.2.1 Morphology

SEM photomicrographs for CA/PHB blends are shown in Figure 3.37.

The selected percentages for cellulose acetate were 20 %, 40 %, 50 %, 60

%. The blends CA/PHB (20/80) (Fig. 3.36a) and CA/PHB (40/60) (Fig.

3.37b) showed two phases where the particles of cellulose acetate (CA) were

dispersed in the PHB matrix. It can be observed that some spherical cellulose

acetate particles were pull out probably due to the low adhesion between

PHB and CA.

The adhesion between CA and PHB appeared to improve when the

cellulose acetate contents were increased as shown in blends CA/PHB

(50/50) (Fig. 3.37c) and CA/PHB (60/40) (Fig. 3.37d). Micrographs (c) and

(d) showed an homogeneous blend.

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130

(a) (b)

(c) (d)

Figure 3.37 SEM Photomicrographs for CA/PHB (20/80)-4000X (a),

CA/PHB (40/60)-2200X (b), CA/PHB (50/50)-1300X (c),

CA/PHB (60/40)-4000X (d).

Subset: high magnification 1000X

3.6.2.2 Thermal Properties

Thermal characterization of neat PHB and CA components and their

blends was performed to obtain informations about degradation, processing

temperatures and the components compatibility(46,53,55).

Attemps were also made to study the thermal properties of PHB, cellulose

acetate (CA) and CA/PHB blends were assessed by thermogravimetry (TGA)

and differential scanning calorimetry (DSC).

Results

131


Figure 3.38 shows the weight loss (a) and the derivative weight loss (b)

traces of CA/PHB blends and the neat polymers. After initial moisture

volatilization between 25°C-120°C, the blends started to degrade in the

temperature range of 200°C–280°C.

The weight losses due to the humidity elimination, were 2.4 %, 4.4 %, 4.5

%, 7.7 % for CA/PHB (20/80), CA/PHB (40/60), CA/PHB (50/50), CA/PHB

(60/40), respectively.

(a) (b)

Figure 3.38 TGA (a) and DTGA (b) Traces for CA/PHB Blends Under


At least four degradation weight loss steps were apparent in the DTGA

traces shown in Fig. 3.38b. The first step corresponded to weight losses of

11.7 % for CA/PHB (20/80), 18 % for CA/PHB (40/60), 26.3 % for CA/PHB

(50/50) and 10.7 % for CA/PHB (40/60). The second steps corresponded to

weight losses of 83.1 % for CA/PHB (20/80), 74.3 % for CA/PHB (40/60),

63.4 % for CA/PHB (50/50) and 54 % for CA/PHB (60/40).

In the third step, decomposition peak as were observed in the

temperature range of 400°C–500°C associated with weight losses of 0.6 %

for CA/PHB (20/80), 1.2 % for CA/PHB (40/60), 1.7 % for CA/PHB (50/50)

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132

and 17.7 % for CA/PHB (60/40). The residue recovered at 800 °C was

around 1-3 % for all selected blends.

PHB started to degrade at 202°C and the residue recovered at 800°C was

0.73 %.

The cellulose acetate (CA) started to degrade at 160°C and the residue

recovered at 800°C was roughly about 8.3 %.

There were four overlapped steps involved in the pyrolysis of cellulose

acetate(53). The first one was connected with the moisture volatilization, it

showed a relative weight loss of ca. 7.6 % and it occurred in the temperature

range of 25°C-130°C.

The second step was in the temperature range of 130°C-210°C with

relative weight loss of 25 %, while the third step was in the range of 210°C-

290°C where the total decomposition of the cellulose structure took place

indicating a weight loss of 38.7 %. The fourth step was comprised in the

temperature range of 290°C-410°C, attributed to the remnant carbon(53) with

relative weight loss of 9.5 %.

The blending of PHB with the cellulose acetate led to increase thermal

stability in the polymeric materials. Infact all the blends had the onset

temperature higher than the PHB which was around 231°C.

The blend CA/PHB (50/50) had a similar thermal behaviour to that of

pristine PHB. Infact its onset temperature was around at 256°C, the closest

value to the PHB onset temperature.

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133

Table 3.28 provides data on the thermal properties for the blends and the

pure polymers.

Table 3.28 Thermal Properties for CA/PHB Blends and the Pristine

Materials Under Nitrogen Atmospherea.


(°C) (°C) (°C) (°C) (°C) (%)

PHB 202 - 217 248a 457 0.73

CA 231 133 174 257 329 8.3

CA/PHB(20/80) 264 108 291 358 - 1.9

CA/PHB(40/60) 271 135 290 355 - 1.6

CA/PHB(50/50) 256 137 289 362 - 1.7

CA/PHB(60/40) 279 154 200 295 352 2.9

a) Ton is the starting degradation temperature, Tp is the main degradation peak, R800 is the

residue at 800°C.

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134


The Figure 3.39 shows the DSC traces for the pristine PHB, cellulose

acetate (CA) and their blends while the Table 3.29 records the relative

thermodynamic properties.

Figure 3.39 DSC Traces for PHB, CA and CA/PHB Blends.

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135

Table 3.29 Thermodynamic Properties for PHB, Cellulose Acetate (CA)

and their Blendsa.

Sample Tg Tm1 ∆Hm1 Tm2 ∆Hm2 Tm3 ∆Hm3

(°C) (°C) (J/g) (°C) (J/g) (°C) (J/g)

PHB 77.49 136 6.93 166 101.41 166 10.64

CA - 42.48 44.12 - - - -

CA/PHB(20/80) - 164 11.69 174 53.15 - -

CA/PHB(40/60) 41 69 24.24 173 70.03 - -

CA/PHB(50/50) 102 - - 173 34.58 - -

CA/PHB(60/40) - 83 24.21 160 8.31 171 20.52

a) Tg = glass transition temperature, Tm = melting temperature, ∆Hm = melting heating.

The DSC traces for CA/PHB blends showed a glass transition temperature

for only CA/PHB (50/50) and CA/PHB (60/40) blends. The values were ca.

41°C for the first sample and ca. 102°C for the second, and the glass

transition temperature for the PHB was around 77°C.

Data indicated that CA made the blends more rigid compared to pure PHB

expecially when the CA percentage was increased up to 50 %.

The two overlapped melting peaks showed enthalpy values of ca. 11.69 Jg-

1 and 53.15 Jg-1 for the CA/PHB (20/80) blend.

The corresponding temperatures were 164°C for the first peak and 174°C

for the second. The melting enthalpy decreased with the increased CA amount

(Table 3.29) but not the temperatures. Also the peaks intensity increased

when the CA content was increased.

The blends CA/PHB (40/60) and CA/PHB (60/40) also showed peaks at

69°C and 83°C corresponding to the moisture volatilization in these two

blends, respectively.

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136

3.6.2.3 Wide Angle X-ray Diffraction (WAXS)

WAXD patterns were performed on CA/PHB blends, where the CA

percentage varied from 20 to 60.

Figure 3.40 shows the WAXD diffraction patterns of pure samples and

their binary blends.

Figure 3.40 WAXD Patterns of Pristine PHB, Cellulose Acetate (CA) and

their Blends.

The x-ray diffraction pattern of PHB is shown in the Figure 3.40.

The pattern of diffraction peaks appeared to be typical of a semi-

crystalline material. Interestingly, the positions and intensities of these

diffraction peaks remained unchanged when PHB was blended with cellulose

acetate indicating that the addition of cellulose acetate didn’t impact in the

semi-crystalline structure of PHB.

3.7 Conclusions

PLABn blends, obtained by compression moulding, were investigated for

their thermal and mechanical properties. The TGA experiments confirmed

the poor plasticizing nature of Bionolle towards the neat PLA, as shown by

the same values for the onset temperature of the two polymers.

Results

137

The 50/50 blend composition showed the same Tg as neat PLA, probably

due to a partial miscibility of the two polymeric materials in this formulation.

YM increased with increasing Bn content, while UTS and EL decreased:

thus the addition of Bn to PLA mixtures is positive for processing and for

composite flexibility.

Also CA/PHB blends, obtained by film casting, were analysed for their

morphological, structural and thermal characteristics.

SEM analysis confirmed an higher adhesion between CA and PHB when

the cellulose acetate contents were increased from 20 to 60 %, while the TGA

analysis pointed out that the blending of PHB with CA improved the thermal

stability of the polymer, as confirmed by the higher value of Ton of the blends

with respect to the pristine PHB.

The 50/50 blend composition showed a Ton value similar to that of PHB

sample, probably due to a miscibility of the two polymeric phases in the

blend.

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138

3.8 Composites Based on Biodegradable Materials and Natural

Organic Fillers

Algae, a low value raw material from renewable resource of marine origin

were proposed for the production of eco-compatible composites.

Fibers derived from the green alga Ulva armoricana, common to French,

Spanish and Italian costs, were evaluated for the production of hybrid films

in combination with polymers, such as poly(hydroxybutirate) (PHB) and

polycaprolacton (PCL)(68,71).

PHB, PCL and Ulva were utilized for the production of hybrid composites

via compression moulding. Results obtained were quite encouraging for

composites showing excellent forming properties and mechanical

characteristics, indicating the suitability of Ulva in plastic formulations due

mostly to significant amounts of crystalline cellulose present as a structural

component of the cell walls(68).

PCL was used to develop composite materials suitable as scaffolds for

bone engineering(69). Scaffolds based on PCL reinforced with long glass

fibres were prepared by using continuous melt impregnation

(extrusion/calendering) and film stacking(70).

Poly(hydroxybutirate) (PHB), is a microbially-derived biodegradable

polyester that has shown a good promise as an alternative to petroleum-based

polymers and for preparing blends incorporating other natural materials.

Because PHB has physical properties quite similar to polypropylene, this

polymer has attracted much attention as a PE substitute for a wide range of

agricultural, marine and medical applications. However, due to its high cost,

currently its use is mainly restricted to medical applications(5).

Injection-molded composites based on PHB or PCL and natural materials,

especially algae, were developed and considered for commercialization in

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139

single use consumer items(6-19). Agriculture (mulch films), packaging,

construction and biomedicine are the sectors where these materials are

expected to final useful applications.

Eco-compatible and biodegradable composites were also produced using

rice which is available in large quantities in Italy. Rice is easily processable

in a twin screw extruder for use in various food and non-food applications.

Biological materials provide a good example of nature’s capacity to

develop functionality in polymers utilizing a variety of approaches(166) that

can be adapted in engineered materials.

For example, self-assembly, self-cleaning and self repair are some

common properties found in natural materials. These functionalities were

simulated in engineered products such as commercially available nano-

particles, sol-gel coatings and dendrite polymers for many useful

applications.

Another approach is to use bio-based materials in a broad range of

products that are biodegradable, lightweight and they have high strength and

antimicrobial activities. Particularly, successful development of diagnostic

products would require broader understanding and creating novel surfaces

with bio-active molecules.

The hybrid materials, where bio-active polymers are combined with

structural polymers is an important area of polymer science. Much focus is

being diverted in developing smart surfaces and intelligent machines using

embedded sensors in materials.

Embedded sensors would allow to monitor the structural health

application of surface coatings and quality of product in response to any

change in the ambient environment.

Beside embedded sensors, could be useful tool in developing

functionalized hybrid materials.

The use of produced hybrid materials was demonstrated in controlling

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140

mechanical vibrations in response to functionalizations in magnetic and

electric fields, as well as in temperature.

The usefulness of such materials in automotive and consumer electronics

is already being recognized, but there is a growing realization that medical

applications will become an increasingly promising area, particularly for

piezoelectric and sensor-suited materials.

Many biodegradable polymers were used in developing products to replace

petrochemicals(167), but most of the research was focused on their

biodegradability aspects.

Now, more themselves, there is a need to establish the safety of these

materials and their by-products when they breakdown in the environment.

To verify their non toxicity, the biodegradation must be carried out in

accelerated laboratory tests where metabolites and residues can be recovered.

To reproduce the natural conditions (compost, field) as closely as possible,

degradation experiments must be run on solid-state substrates. In this regard,

Grima et al.(167) reviewed aerobic degradation in solid-state substrates,

focusing in particular on the environmental, physical, and chemical

parameters, such as substrate nature, moisture, temperature, C/N ratio, and pH

which influence biodegradation kinetics. This study also aimed at finding the

solid substrate most suitable for residues and metabolites recovery.

The most significant parameters would appear to be the substrate type,

moisture content, and temperature. Inert substrates such as vermiculite were

found to be well suited for the residue extraction.

This review also opened the field to new research aimed at optimizing

conditions for aerobic solid-state biodegradation and at recovering the

metabolites and residues, generated during the degradation process.

In this report, the external parameters that influence biodegradation

kinetics were presented. These included the material concentration in the

solid medium, the environmental conditions (temperature, pH, moisture,

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141

oxygen availability, composition and concentration of inorganic nutrients of

the solid medium), the microbial population (concentration, nature, and

interactions), the presence or absence of other degradable substances, and the

conditions and properties of the test system (volume and shape of the

vessels).

Also the measurement procedures currently used in laboratory for solid-

state fermentation were examined in detail and issues related to residue

recovery were addressed.

Today’s consumer plastics are designed with little consideration for their

ultimate disposability or the impact of feedstock used in making them(187),

which led to unintended environmental consequences.

This created a need to design and engineer products using biodegradable

polymers that had the performance characteristics of today’s materials but

biodegrade upon disposal in soil into humic substances.

Many farm derived and bio-derived polymers such as starch, cellulose and

protein oils are excellent raw material for obtaining chemicals,

pharmaceuticals and nutraceuticals as well as for manufacturing plastic

composites.

In this regard, soy proteins were compounded with synthetic

biodegradable plastics such as polycaprolacton or poly (lactic acid) to make

molded products, edible films and or shopping bags indicating a promising

future for such materials in bringing real environmental benefits.

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142

3.8.1 Organic Fillers

3.8.1.1 Ulva Fibres

3.8.1.1.1 Morphology

Fiber size, along with their morphology, surface characteristics, dispersion

in the polymer matrix and its compatibility with other adjuvants are all

important determinants in dictating the overall quality of the composites.

For this purpose, efforts were made to investigate the size distribution of

fibers in ulva preparation.

Results are presented in Table 3.30 which shows the dimensional

distribution of micronized ulva obtained using standard sieves asper ASTM.

More than 60 % of ulva fibers were found to be above 0.212 mm in

length.

Table 3.30 Micronized Ulva Fibres Distribution.

Mesh (mm) U

(%)

40 φ > 0.425 0.2

40-50 0.300 < φ < 0.425 0.2

50-70 0.212 < φ < 0.300 3.4

70-100 0.150 < φ < 0.212 13.2

100-140 0.100 < φ < 0.150 30.9

140-270 0.053 < φ < 0.100 19.0

270 φ < 0.053 33.1

Fibers granulometry for ulva used as a filler could be an important tool for

composites production.

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143

Figure 3.41 shows the micrometric dimension of ulva particles that create

aggregates in the material. The ulva fiber appeared as an homogenous

material.

Figure 3.41 SEM Photomicrograph for Micronized Ulva-250X.

3.8.1.1.2 Thermal Properties

For a successful melt processing, it is critically important the information

on its thermal stability is available. Therefore, ulva fibers were processed and

evaluated to obtain information on their degradation temperature for material

processing.

Figure 3.42 shows TGA and DTGA traces for the micronized ulva.

Figure 3.42 TGA and DTGA Traces for Ulva Fibres.

After an initial loss of 6.1 % at temperature ranging between 25°C-144°C,

attributed mostly to humidity and volatiles, micronized ulva fibers started to

decompose at a temperature around at 221°C.

Results

144

Two decomposition peaks were evident; the first at 237°C and the second

peak at 693°C. The first peak was in the temperature range of 200°C-500°C

while the second one was in the temperature range of 650°C-730°C and the

weight losses associated with them were 22.1 % and 8.8 %, respectively. The

first peak showed two overlapped shoulders that were in the temperature

range of 300°C-430°C and 430°C-500°C and with corresponding weight

losses of 15.2 % and 2.9 %, respectively.

The residue recovered at 800 °C was about 41 % which was due to the

high amount of inorganic salts and siliceous materials present in algal

sample.

3.8.1.1.3 Infrared Spectroscopy

Algal samples were further characterized using infrared spectroscopy.

Figure 3.43 shows the IR spectrum of micronized ulva and Table 3.31

reports the principal wavenumbers for this material.

Figure 3.43 Ulva IR Spectrum.

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145


Micronized Ulva.

Functional Groups Wavenumbers

(cm-1)

O-H stretching 3420

C-H stretching 2920-2850

C=O stretching 1655

CH2 bending 1420

C-O stretching 1256-1030

C-H bending 840

Spectrum appeared to be quite typical of a plant material with a strong

absorption in the OH region indicative of hydroxyl containing entities in the

sample such as cellulose and the polysaccharides.

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146

3.8.1.2 Ground Rice, Chaff and Farinaccio


Table 3.32 shows the size distribution of ground rice obtained using

standard ASTM protocols.

Table 3.32 Ground Rice Granules Distribution.

Mesh (mm) U

(%)

40 φ > 0.425 0.1

40-50 0.300 < φ < 0.425 0.2

50-70 0.212 < φ < 0.300 0.8

70-100 0.150 < φ < 0.212 35.1

100-140 0.100 < φ < 0.150 36.1

140-270 0.053 < φ < 0.100 25.9

270 φ < 0.053 1.7

The size distribution analyses of ground rice granules indicated that over

95 % the granules were within the size range of 0.06-0.212 mm.

Figure 3.44 shows the SEM photomicrograph for the ground rice granules.

The picture presented zones with aggregates of big dimensions,

confirming the homogenous nature of this material.

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147

Figure 3.44 SEM Photomicrograph for Ground Rice-200X.

Table 3.33 shows the size distribution of chaff granules.

Table 3.33 Chaff Granules Distribution.

Mesh (mm) P

(%)

30 φ > 0.06 26.38

30-40 0.425 < φ < 0.06 14.01

50-70 0.212 < φ < 0.300 40.32

70-100 0.150 < < 0.212 14.92

100-140 0.100 < φ < 0.150 4.06

140-270 0.053 < φ < 0.100 1.5

270 φ < 0.053 0

The size distribution analyses of chaff granules indicated that over 95 %

the granules were within the size range of 0.06-0.212 mm which was quite

distinct compared to the micronized ulva and ground rice samples.

SEM analysis of chaff confirmed the presence of large aggregates

compared to the other fillers. Chaff appeared to be a suitable heterogeneous

material for use as fillers in making composites.

Figure 3.45 shows the SEM photomicrograph for the chaff.

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148

Figure 3.45 SEM Photomicrograph for Chaff-200X.

Table 3.34 shows the dimensional distribution of farinaccio obtained by

standard sieving procedures.

Table 3.34 Farinaccio Granules Distribution.

Mesh (mm) Fc (%)

30 φ > 0.06 15.94

30-40 0.425 < φ < 0.06 12.14

40-50 0.300 < φ < 0.425 20.66

50-70 0.212 < φ < 0.300 16.64

70-100 0.150 < φ < 0.212 22.57

100-140 0.100 < φ < 0.150 8.99

140-270 0.053< φ < 0.100 3.05

270 φ < 0.053 0

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149

Figure 3.46 shows the SEM photomicrograph for rice farinaccio.

Figure 3.46 SEM Photomicrograph for Farinaccio-150X.

SEM photomicrograph of farinaccio showed mostly huge aggregates

compared to the chaff. The aggregates had medium size dimensions and the

material appeared only as an homogeneous phase.

Probably the grinding process of the material created some superficial

zones of gelatinization or proteins and polysaccharides intercalation. Also

this raw material is suitable as filler in making bio-composites.


Figure 3.47 shows TGA and DTGA trace for the ground rice.

Figure 3.47 TGA and DTGA Trace for Ground Rice.

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150

Initial weight loss attributed to the loss of humidity and other volatile

compounds was 11.2 %. The decomposition temperature of ground rice was

around at 280°C and only one decomposition peak was observed which was

correlated with the decomposition of amidaceous substances. The relative

weight loss at this step was 82.3 %.

The residues recovered at 800 °C were about 15 %. The high amount of

residues are indicative of an high fiber content in the samples.

Figure 3.48 shows TGA and DTGA chaff (a) and farinaccio (b) traces.

100

80

60

40

20

0

Wei

ght L

oss

(%)

8007006005004003002001000

Temperature (°C)

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0D

erivative Weight loss (%

/°C)

100

80

60

40

20

0

Wei

ght L

oss

(%)

8007006005004003002001000

Temperature (°C)

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

Derivative W

eight Loss (%/°C

)

(a) (b)

Figure 3.48 TGA and DTGA Traces for Chaff (a) and Farinaccio (b).

After initial weight losses, both chaff and farinaccio samples degraded at

much lower temperatures when compared to ulva and ground rice. This

pointed to the creating evident challenges of processing complex organic

matter with polymers.

There were three overlapped decomposition peaks for chaff and four ones

for farinaccio, that ranged between 170°C-300°C.

The weight losses were 7.8 %, 37.7 % for the chaff and 15.4 % for the

farinaccio.

The residues recovered at 800 °C were around 22.4 % for chaff and 20 %

for farinaccio due to high fibrous component in the samples.

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151

Table 3.35 records the thermal properties for the fibers under nitrogen

atmosphere.

Table 3.35 Thermal Properties for the Fibres Under Nitrogen

Atmosphere.


(°C) (°C) (°C) (°C) (%)

Ulva 221 62 228 671 41

Ground Rice 280 309 - - 15

Chaff 169 208 301 335 22.4

Farinaccio 179 207 301 331 20

The onset temperature for these fibres was comprised between 170°C and

280°C. Both chaff and farinaccio are ground rice by-products and they

indicated a much lower thermal stability compared to the ground rice itself.

Ulva fibre exhibited an intermediate behaviour with an higher Ton than

rice by-products but a much lower Ton compared to rice. This behaviour and

significantly higher residues recovered at 800°C were indicative of siliceous

components present in the material.

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152

3.8.1.2.3 Infrared Spectroscopy (FTIR)

Figure 3.49 shows the IR spectrum of the ground rice and Table 3.36


Figure 3.49 Ground Rice IR Spectrum.


Ground Rice.


(cm-1)

O-H stretching 3380


C=O stretching 1650


C-H bending 570

Spectrum presented a strong absorption in the OH region indicative of

hydroxyl containing entities in the sample such as starch and amilopectin.

Also the C=O and C-H stretching were evident in the spectrum.

Figure 3.50 shows the IR spectrum of the chaff and Table 3.37 reports the

principal wavenumbers for this sample.

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153

Figure 3.50 Chaff IR Spectrum.


Chaff.


(cm-1)

O-H stretching 3400


C=O stretching 1710


CH2 bending 1650-1460

C-H bending 710

Figure 3.51 shows the IR spectrum of the farinaccio and Table 3.38


Figure 3.51 Farinaccio IR Spectrum.

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154


Farinaccio.


(cm-1)

O-H stretching 3390-3100


C=O stretching 1650

C-O stretching 1050

CH2 bending 1540

Both chaff and farinaccio showed the typical absorptions of hydroxyl and

carboxylic groups present in the materials. Also the stretching and bending of

C-H and CH2 were visible and in good agreement with the spectrum graph.

3.8.1.3 Polymeric Materials


When we have to make blends and composites, it is important to evaluate

the polymer thermal stability and degradation temperature for obtaining

useful informations on the melt processing conditions.

So the thermogravimetric analysis led us to improve the knowledgement

on hydrolene (LFT) (a) and polyvinyl alcohol (PVA 18/88) (b) which TGA

and DTGA traces are reported in Figure 3.52.

Results

155

(a) (b)

Figure 3.52 TGA and DTGA Traces of Hydrolene (LFT) (a) and

Polyvinylalcohol (PVA 18/88) (b).

Initial weight loss in LFT, which was a mixture of PVA by-products and

inks, was 3.8 % in the temperature range of 25°C-142°C. Two main

decomposition peaks were observed in hydrolene samples at 322°C and

439°C. The corresponding weight losses at these temperatures were 51.6 %

and 12 %, respectively.

For the first peak, the trace showed two shoulders at the temperature

around at 214°C and 278°C with associated weight losses of 15.2 % and 13

%, respectively. The residue recovered at 600 °C was 3.7 % and it was higher

than many other polymeric materials.

PVA samples showed an initial weight loss around at 2.55 % between

25°C-178°C. The decomposition trace showed two PVA decomposition

peaks around at 318°C and 428°C. The corresponding weight losses were

74.6 % and 18.4 % and the residue recovered at 600 °C was 4.1 %.

The presence of additives, in the hydrolene, made this material thermally

less stable than PVA. Infact its Ton was 234°C, compared to PVA which was

around 271°C.

Figure 3.53 shows TGA and DTGA traces for PHB (a) and PCL 6500 (b).

100908070605040302010

0

Peso

Res

iduo

(%)

6005004003002001000Temperatura (°C)

1.2

0.9

0.6

0.3

0.0

Derivata (%

/ °C)

Results

156

100

908070605040302010

0

Peso

Res

iduo

(%)

6005004003002001000Temperatura (°C)

5

4

3

2

1

0

Derivata (%

/°C)

100

90

80

70

60

50

40

30

20

10

0

Wei

ght L

oss

(%)

6005004003002001000Temperature (° C)

2.4

2.1

1.8

1.5

1.2

0.9

0.6

0.3

0.0

Derivative W

eight Loss ( %/°C

)

(a) (b)

Figure 3.53 TGA and DTGA Traces of PHB (a) and PCL 6500 (b).

The thermal properties of these leading biodegradable polymers such as

PHB, PCL (PCL 6500) and PLA were also carried out for comparative

pourpouses. PHB and PCL showed initial weight losses of 0.03 % and 0.24

%, respectively. Poly(hydroxybutirate) (PHB) started to decompose around at

239°C and a single decomposition peak was observed around at 260°C.

The weight loss associated with this peak was 98 %. The total residue

recovered at 800°C was 0.48 %.

PCL, on the other hand, started to decompose around at 362°C with a

single decomposition peak at 404°C. The associated weight loss was 25.3 %.

The residue recovered at 800°C was 0.16 %.

Figure 3.54 shows TGA and DTGA traces for poly-lactic acid (PLA).

Figure 3.54 TGA and DTGA Traces for PLA.

Results

157

PLA had a some what higher initial weight loss compared to PHB and

PCL. The weight loss in PLA was 0.31 % in the temperature range of 25°C-

256°C. PLA started to decompose around at 320°C and a single degradation

peak was observed. The residues obtained at 800°C was roughly 1.01 %.

Table 3.39 records the thermal properties for the polymeric material under

nitrogen atmosphere while Table 3.40 reports the thermodynamic parameters

for the selected polymeric materials.

Table 3.39 Thermal Properties for the Polymeric Materials Under


Sample Ton Tp1 Tp2 R800

(°C) (°C) (°C) (%)

Bionolle 1020 350 412 - 1.4

Bionolle 1050 348 412 - 0.7

PLA 326 364 - 0.4

PLAc 302 354 - 0.1

PHB 281 302 - 3.0

PHBd 239 258 - 0.5

PCL 6500d 320 403 - 0.2

PCL 6500e 362 404 - 0.7

LFT rig Verded 188 439 322 3.7

PVA 18/88 264 316 426 4.1

PLA c = PLA after Brabender processing, d = samples analyzed at 800°C, e = PCL 6500 after

Brabender processing.

For the biodegradable polymers, the Ton values (Table 3.39) were higher

for PHB and PLA processed at Braebender in comparison to the pure

materials. The only exception was PCL 6500, for which the Braebender

processing improved the thermal stability.

Results

158

The only material that presented an high residue recovered at 800°C, was

hydrolene (LFT), due to the additives introduction in the material.

This was the same reason for which all materials had only one

decomposition peak except LFT polymer.

Table 3.40 Thermodynamic Properties for Polymeric Materials.

Sample Tg Tc ∆Hc Tm2 ∆Hm2

(°C) (°C) (J/g) (°C) (J/g)

Bionolle 1020 -33.1 - 113.5 103.7 27.9

Bionolle 1050 -32.4 - 113.5 100.9 14.3

PLA 63.9 - - 154.7 28.6

PHB 0.9 56.5 53.3 173.1 82.5

PCL 6500 - 22.2 93.1 55.9 78.8

LFT 55.3 125.9 21.4 173.4 16.0

The glass transition temperature (Tg) presented an high positive value only

for PLA, confirming the rigidity of the material and the need to plasticize it

in making composites.

The cold crystallization enthalpy was quite high for Bionolle and PCL

6500, while the melting enthalpy was high for PHB and PCL 6500. These

two polymers also had high melting enthalpy values (82.5 J/g for PHB and

78.8 J/g for PCL 6500) compared to the other polymers.

3.8.1.4 Composites based on PCL/ulva


Fibers were well dispersed throughout the matrix and exhibited

considerable cohesion with the polymer. At the macroscopic level, film was

Results

159

smooth, flexible and strong, but a microscopic examination revealed the

presence of regions with exposed fibers or fibers aggregates.

These inconsistencies might have resulted from the imprecise control of

the film thickness from compression moulding.

Figure 3.55 shows the SEM photomicrographs for the PCL 6500 (a) and a

PCL blend containing 30 % of ulva as a biological filler (b).

(a) (b)

Figure 3.55 SEM Photomicrographs for PCL 6500-1000X (a) and

PCLU30-1000X (b).

A good compatibility appeared to be at the interface between PCL and

ulva. However some inconsistencies were noted throught the matrix.

Both, PCL 6500 and the blend PCLU30 showed a smooth surface where

the fibers were quite well dispersed in the polymer matrix making the film

stronger when the filler agent was present.


Figure 3.56 shows the TGA (a) and DTGA (b) traces for the selected

compositions of PCL/Ulva (70/30, 50/50, 30/70) composites and for the

pristine materials.

The first step corresponded to the humidity and volatiles elimination and it

Results

160

occurred in the temperature range of 25°C-100°C. The weight losses were 1.2

% for PCLU30, 2.7 % for PCLU50 and 2.3 % for PCLU70.

The Ton was between 350°C and 365°C for all PCLU composites. With

increased fiber content, a decrease in the thermal stability was observed in

composite.

(a) (b)

Figure 3.56 TGA (a) and DTGA (b) Traces for PCL/Ulva Composites.

PCLU30 blend showed two degradation peaks that fall down around at

235°C and 396°C with associated weight losses of 10.7 % and 70 %,

respectively.

PCLU50 trace also showed two peaks at 237°C and 384°C. The weight

losses corresponding to these steps were 13.5 % and 50 % respectively.

For PCLU70 samples, peaks were observed at 234°C and 378°C, with

their relative weight losses of 18.3 % and 33.7 %, respectively.

The residue recovered at 600 °C increased proportionally with increased

ulva content which was doing to the high quantity of siliceous material in

algal cell mass. The values were 16 % (PCLU30), 23 % (PCLU50) and 33.5

% (PCLU70) respectively.

Results

161

Table 3.41 records the thermal properties for the selected composites.

Table 3.41 Thermal Properties for the PCL/Ulva Composites.


(°C) (°C) (°C) (°C) (%)

PCLU30 365 235 396 - 16.0

PCLU50 359 119 237 384 23.0

PCLU70 350 120 234 378 33.5

Ton was found to be between 350°C-370°C and the loss of thermal

stability was proportional to the amount of fibers in the samples.

Figure 3.57 Ton and Residue Trend for PCL/Ulva Composites.

The Ton and residue trend for PCL/Ulva composites is shown in Figure

3.57.

370

360

350

T on(

°C)

7060504030

Ulva (%)

40

30

20

10

Residue (%

)

Results

162

There was an inverse proportionality between the two parameters: the

increase in the percent of ulva reduced the composite thermal stability

connected with an increased siliceous material amount, which did not

pyrolize at 600°C.

The 50 % algal content seemed to be a critical concentration: from this

point the thermal stability started to be strongly affected to the presence of an

high recovered residue.

Results

163


The DSC traces for the composites based on PCL/Ulva and the pristine

materials are provided in Figure 3.58.

-8

-6

-4

-2

0

2

4

6

8

Hea

t Flo

w (W

g-1)

100500

Temperature (°C)

PCLU30

PCL6500

PCLU5

PCLU20

PCLU40

PCLU50

PCLU60

Ulva

Figure 3.58 DSC Traces for PCL/Ulva Composites.

The DSC traces showed single melting peak for all PCL/Ulva

formulations. The only exception was the composite PCLU20 which showed

a double melting peak, connected with the algal components, for this

particular formulation.

Table 3.42 records the thermodynamic parameters for the PCL/Ulva

composites.

Results

164

Table 3.42 Thermodynamic Properties for PCL/Ulva Composites.

Sample Tc ∆Hc Tm1 ∆Hm1 Tm2 ∆Hm2

(°C) (J/g) (°C) (J/g) (°C) (J/g)

PCL 29.39 -78.7 56.14 66.75 - -

PCLU5 31.49 -80.46 57.45 65.9 - -

PCLU10 31.37 -67.62 55.88 56.04 - -

PCLU20 31.25 -68.03 56.02 35.14 57.8 20.77

PCLU30 31.81 -59.82 55.93 48.93 - -

PCLU40 31.59 -51.49 56.29 41.94 - -

PCLU50 33.59 -41.98 55.97 35.75 - -

PCLU60 33.62 -33.64 55.52 29.02 - -

The data presented in Table 3.42 showed a progressive decreasing in

melting heat (∆Hm ) with increased algal content. The organic fillers probably

contributed towards the mobility of the polymeric chains, thus decreasing the

demand for the energy required for the melting of the polymeric material.

Also a decrease in the crystallization heat was observed, because of the

composites lost some of their crystallinity due to the presence of the organic

fillers, that acted as a nucleating agent for the crystallization of polymer

chains(87,91). The filler did not appear to have any impact on the glass

transition temperature (Tg) of PCL that was observed at -60°C for all samples

tested.

The melting temperature in most composites was in close proximity to that

of neat PCL(89,90). The decrease in blend’s crystallinity was due to the

presence of algal biomass, probably interfered with the movements of

polymer chain, thus impacting its morphology and amorphous behaviour.

Results

165

3.8.1.4.4 Mechanical Properties

The specimens in the shape of dog-bones were stamped out and tested for

their mechanical properties. Before testing, specimens were preconditioned at

50 % relative humidity. The results from the Instron test are provided in

Table 3.43

Table 3.43 Mechanical Properties for the PCL/Ulva Composites.

Sample El StDv UTS StDv YM StDv

(%) (MPa) (MPa)

PCL 813 87 26.8 3.7 374 7

PCLU30 75 18 7.5 0.8 472 28

PCLU40 33 17 8.2 0.9 652 35

PCLU50 6 1.5 6.6 0.7 779 0.15

PCLU60 3 0.7 6.1 0.8 789 82

PCLU70 1 0.3 3.2 0.8 465 101 El = Elongation at Break, UTS = Ultimate Tensile Strength, YM = Young Modulus,

StDv = Standard Deviation.

PCL is a thermoplastic and ductile polymer(89) and the laminates produced

from it had an high elongation at break (> 800 %). The addition of ulva

improved the Young Modulus (YM) of the blends with a loss of both El and

UTS that showed a concomitant decrease. Thus, ulva was only suitable as

filler and it was not recommended as a reinforcement in blends.

Particularly, when the ulva content was greater than 40 %, the elongation

at break (EL) was drastically impacted the UTS showing only a modest

change when Ulva content ranged between 30 and 60 percent. The blend with

70 % Ulva content (PCLU70) was very fragile.

Results

166

3.8.1.5 Composites based on PHB/Ulva


The SEM photomicrographs for the PHB composites containing 30 % (a)

and 50 % (b) of ulva are shown in Figure 3.59.

(a) (b)

Figure 3.59 SEM Photomicrographs for PHBU30-1000X (a) and

PHBU50-1000X (b).

When examined visibly, composites showed a rather smooth surface.

However, few SEM inconsistencies were obvious. Some cracks were

visible at the interface between the polymer matrix and algal material.

The cracks were an indication of a poor compatibility between these two

materials. In the formulation with 50 % algal content (PHBU50), the ulva

fibre formed large aggregates dispersed throughout the polymeric matrix.


The TGA (a) and DTGA (b) traces for the selected PHB/Ulva

compositions (70/30 and 50/50) and pristine materials are presented in Figure

3.60.

Results

167

Both composites showed an humidity and volatiles elimination in the

temperature range of 25°C-100°C and their corresponding weight losses were

1.1 % (PHBU30) and 1.4 % (PHBU50).

Both PHBU30 and PHBU50 started to decompose at a temperature around

at 266°C.

The main decomposition peak occurred between 240°C-300°C and the

weight losses were 74.05 % for PHBU30 and 57.9 % for PHBU50.

It represented the total pyrolysis of the polymeric material. This peak

showed a shoulder in both DTGA traces (Fig. 3.59b) that felt down in the

temperature range of ca. 190°C-240°C corresponding to a weight losses of

4.3 % for PHBU30 and 6.9 % for PHBU50.

The residue recovered at 600 °C increased with the alga content

confirming that the ulva contains an high quantity of siliceous materials. The

values were 14.2 % for PHBU30 and 22.5 % for PHBU50.

(a) (b)

Figure 3.60 TGA (a) and DTGA (b) Traces for PHB/Ulva Composites.

The DTGA trace (Fig. 3.60b) showed that the two peaks of the pure

components were shifted towards intermediate values indicating that the

thermal stability depended on the presence of Ulva that was present in the

composites.

Table 3.44 records the thermal properties for PHB/Ulva composites.

Results

168

Table 3.44 Thermal Properties for the PHB/Ulva Composites.


(°C) (°C) (°C) (°C) (%)

PHBU30 268 234a 279 - 14.2

PHBU50 265 232a 279 - 22.5

a: shoulder

Both formulations PHBU30 and PHBU50 showed the same thermal

stability as indicated by the similar Ton values. Also the degradation effects

were the same in both formulations confirming that the algal biomass acted

only as a filler agent.

Results

169


Figure 3.61 shows the DSC traces for the composites based on

PHB/Ulva and the pristine materials.

-6

-4

-2

0

2

4

6

Hea

t Flo

w (W

g-1)

200150100500

Temperature (°C)

PHB

PHBU30

PHBU40

PHBU10

PHBU20

PHBU5

Ulva

Figure 3.61 DSC Traces for the PHB/Ulva Composites.

Composites blended with variable amount of Ulva fibers was processed in

a Braebender and analyzed along with PHB controls. DSC traces for all

samples indicated a double fusion peak similar in the shape and temperature

value.

Table 3.45 records the thermodynamic properties for the PHB/Ulva

composites.

Results

170

Table 3.45 Thermodynamic Properties for the PHB/Ulva Composites.

Sample Tc ∆Hc Tm1 ∆Hm1 Tm2 ∆Hm2

(°C) (J/g) (°C) (J/g) (°C) (J/g)

PHB 90.38 -94.37 167 55.04 173 35.48

PHBU5 85.55 -48.61 176 26.72 181 28.68

PHBU10 91.82 -69.55 166 49.98 173 28.55

PHBU20 91.09 -62.71 167 42.78 173 25.86

PHBU30 91.04 -54.76 168 32.71 173 23.5

PHBU40 92.02 -44.84 165 28.31 173 19.24

Addition of only 5 % algal content resulted in a melting temperature

increase(22) of about 10°C in blends. Interestingly, only half as much heat

( ∆Hm), was required to meet PHB blended with algae compared to neat

PHB.

This indicated that the algal biomass had an impact on the melting heat

( ∆Hm) of the PHB polymer in the blend.

Results

171


After conditioning at 50 % relative humidity, the PHBU20 and PHBU30

dog bone specimens were analyzed for their mechanical properties as

reported in Table3.46.

Table 3.46 Mechanical Properties for the Composites PHBU20 and

PHBU30.


(%) (MPa) (MPa)

PHBU20 1.2 0.1 19.1 2.9 2209.6 163.7

PHBU30 1.1 0.1 15.3 2.0 2280.6 282.6

El = Elongation at break, UTS = Ultimate tensile strength, YM = Young Modulus, StDv =

Standard deviation.

Samples had a low elongation at break due to the inconsistencies present

in the laminates containing ulva fibres. The Young Modulus (YM) increased

gradually with the uniform increment of ulva fibre loading in the

composite(93).

3.8.1.6 Composites based on PHB/PCL


Figure 3.62 shows the TGA (a) and DTGA (b) traces for several selected

PHB/PCL compositions (10/90, 20/80, 30/70, 90/10, 80/20, 70/30).

For all composites, the humidity and volatiles elimination occurred at

temperature between 25°C-100°C and the weight losses at this step were 0.02

% for PHB10PCL90, 0.003 % for PHB20PCL80, 0.07 % for PHB30PCL70,

Results

172

0.13 % for PHB70PCL30, 0.18 % for PHB80PCL20 and 0.012 % for

PHB90PCL10.

Composites with high percentage of PCL started to degrade in a

temperature range comprised between 370°C and 385°C. Whereas,

composites with high percentage of PHB started to degrade between 230°C-

280°C..

The data indicated that composites with high amount of PCL were much

more thermally stable than PHB composites.

Two decomposition peaks were evident for all composites and their

intensity varied depending on the polymer (PHB or PCL) amount present in

the composite, recovered from pyrolysis during the TGA experiments.

In the first step, the temperature felt down in the range of 200°C-340°C

and the corresponding weight losses were 10.7 % for PHB10PCL90, 20 %

for PHB20PCL80, 30.4 % for PHB30PCL70, 68 % for PHB70PCL30, 72.4

% for PHB80PCL20 and 88 % for PHB90PCL10.

Interestingly, the weight loss steps showed an increase in their values

when the amount of PHB was increased.

The second step occurred in the temperature range of ca. 280°C-500°C

and the corresponding weight losses were 88.3 % for PHB10PCL90, 79.5 %

for PHB20PCL80, 69.1 % for PHB30PCL70, 24 % for PHB70PCL30, 21 %

for PHB80PCL20 and 11.6 % for PHB90PCL10.

The second DTGA peak also showed two shoulders for the composite

PHB70PCL30 in the temperature range of 350°C-390°C, which were

attributed to the pyrolysis effects of some impurities present in the pristine

PCL. This was completely opposite to what was observed in the first DTGA

peak.

The residue recovered at 800°C included some partially pyrolyzed part of

the polymeric material estimated to be around 0.64 % for PHB10PCL90, 0.43

Results

173

% for PHB20PCL80, 0.55 % for PHB30PCL70, 0.03 % for PHB70PCL30,

1.01 % for PHB80PCL20 and 0.46 % for PHB90PCL10.

Table 3.47 records the thermal properties for the PHB/PCL composites.

(a) (b)

(a) (b)

Figure 3.62 TGA (a) and DTGA (b) Traces for PHBPCL Composites.

Table 3.47 Thermal Properties for the PHBPCL Composites.


(°C) (°C) (°C) (°C) (%)

PHB10PCL90 290 308 411 - 0.64

PHB20PCL80 289 302 409 - 0.43

PHB30PCL70 285 300 408 - 0.55

PHB90PCL10 274 294 403 - 0.46

PHB80PCL20 246 258 304 425 0.99

PHB70PCL30 236 255 315 380 0.00

The thermal stability of PHB and PCL blends was directly proportional to

the amount of PCL present in the composites (Table 3.47). The blend

PCLU30 seemed to be less thermally stable compared to the other

formulations, which had higher Ton, decreasing or increasing the algal content

in the blend.

Results

174


Figure 3.63 shows the DSC traces for the PHBPCL composites.

-8

-6

-4

-2

0

2

4

6

8

Hea

t Flo

w (W

g-1)

200150100500

Temperature (°C)

PHB10PCL90

PHB20PCL80

PHB30PCL70

PHB50PCL50

PHB70PCL30

PHB80PCL20

PHB90PCL10

PCL 6500

PHB

Figure 3.63 DSC Traces for the PHBPCL Composites.

All the DSC traces showed the PCL melting peak near 60°C. The peak

intensities decreased considerably as the amount of PCL polymer decreased

in the blends.

A second PHB melting peak was also apparent at 170°C in all

formulations. The peak intensity increased with increased PHB content in the

blend.

The decrease in the heat flow for PHB composites was noted increased

PHB content. The heat flow of 6 J/g was observed in composites with 90 %

Results

175

PHB content. The heat flow of PCL showed an increase, depending on the

PHB content in composites.

Table 3.48 records the thermodynamic properties for the composites based

on PHB and PCL.

The melting enthalpy showed a trend similar to that of melting

temperature indicating a decrease in melting enthalpy with a decrease in PCL

percentage and an increase in melting enthalpy with an increase in PHB

content.

Table 3.48 Thermodynamic Properties for the PHBPCL Composites.

Sample Tm1 ∆Hm1 Tm2 ∆Hm2 Tm3 ∆Hm3

(°C) (J/g) (°C) (J/g) (°C) (J/g)

PHB10PCL90 56.17 51.14 165.65 2.17 172.3 3.49

PHB20PCL80 56.59 41.64 163.58 3.40 172.49 10.10

PHB30PCL70 56.39 36.11 165.01 3.62 172.38 16.45

PHB50PCL50 55.97 26.87 164.45 15.23 172.70 24.61

PHB70PCL30 56.16 12.49 163.87 12.94 172.28 30.95

PHB80PCL20 56.14 10.90 165.45 40.00 172.55 36.04

PHB90PCL10 55.87 4.93 165.47 21.78 173.15 46.02

Results

176


After conditioning (50 % RH), selected PHBPCL specimens were analyzed

for their mechanical properties. Data are presented in Table 3.49.

Table 3.49 Mechanical Properties for the PHBPCL Composites.


(%) (%) (MPa)

PHB10PCL90 631 63 20.1 1.8 436 8

PHB20PCL80 590 22 16 1.3 470 35

PHB30PCL70 532 18 11.9 0.9 501 42

PHB50PCL50 2.5 0.2 9.8 1.8 676 103

PHB70PCL30 4.0 0.4 22.5 1.9 1427 135

PHB80PCL20 6.4 1.1 26.9 5.2 1297 72

PHB90PCL10 7.81 0.8 30.6 3.8 1604 89

Figure 3.64 shows the mechanical properties of PHBPCL composites.


Modulus for the PHBPCL Composites.

Results

177

PCL is a thermoplastic polymer and as expected showed an excellent

elongation at break (EL) without any additives. The laminates based on PCL

with added PHB polymer had a negative impact on its elongation.

Addition of a small quantity of PHB polymer resulted in a decrease in

elongation at break.

In a 50/50 PHBPCL blend, EL decreased from 800 % to almost zero

percent yielding a fragile material. The effect on UTS was only evident when

PHB content increased over 50 % in the blend. Young Modulus (YM) stayed

small through out and any variations in PHB or PCL did not have any impact

on the YM of the composite.

3.8.1.7 Composites based on PHBPCL/Ulva


Figures 3.65 and 3.66 show the TGA (a) and DTGA (b) traces for selected

PHB/PCL composites containing 10 %, 20 % and 30 % of ulva..

Weight losses due to humidity and volatiles elimination, that occurred in

the temperature range of 25°C-100 were 0.04 % for (PHB80PCL20)90U10,

0.13 % for (PHB80PCL20)80U20, 1.5 % for (PHB80PCL20)70U30, 0.5 %

for (PHB70PCL30)90U10, 0.18 % for (PHB70PCL30)80U20 and 0.34 % for

(PHB70PCL30)70U30.

The DTGA traces (Fig. 3.65b and 3.66b) showed two weight loss steps,

typical of pyrolyzed polymeric materials occurred in the temperature range of

200°C-360°C and 200°C-300°C. The weight losses associated with the first

and the second step were 71.75 % and 14.42 % for (PHB80PCL20)90U10,

66.4 % and 3.04 % for (PHB80PCL20)80U20, 63.7 % and 16.7 % for

(PHB80PCL20)70U30, 63.8 % and 23.8 % for (PHB70PCL30)90U10, 60.05

% and 26.9 % for (PHB70PCL30)80U20, 51.35 % and 25.6 % for

(PHB70PCL30)70U30.

Results

178

In PHB/PCL (80/20) blends containing 10 and 20 % of ulva, the second

peak showed a shoulder, that felt down in the temperature range of ca.

300°C-360°C. The weight losses were 5.7 % for (PHB80PCL20)90U10 and

18.02 % for (PHB80PCL20)80U20.

The residue recovered at 800°C increased with an increase in the algal

content, as this material had a large quantity of siliceous material, which was

only partially pyrolyzed at 800 °C.

The weights obtained were 3.1 % for (PHB80PCL20)90U10, 7.9 % for

(PHB80PCL20)80U20, 11.3 % for (PHB80PCL20)70U30, 3.0 % for

(PHB70PCL30)90U10, 7.2 % for (PHB70PCL30)80U20 and 11.8 % for

(PHB70PCL30)70U30.

The DTGA traces (Fig.3.66b) showed sharp but narrowly spaced

degradation peaks for PHB/PCL and Ulva blends. Table 3.50 records the

thermal properties for the PHBPCL/Ulva composites.

(a) (b)


Composite.

Results

179

(a) (b)


Composite.

Table 3.50 Thermal Properties for the PHBPCL/Ulva Composites.


(°C) (°C) (°C) (°C) (°C) (%)

PHB80PCL20 247 257 303 424 - 1.01

(PHB80PCL20)90U10 246 273 327a 382 420 3.07

(PHB80PCL20)80U20 249 263 335 379 428 7.9

(PHB80PCL20)70U30 258 233a 282 389 696 11.3

PHB70PCL30 235 255 315 356 380 0.0

(PHB70PCL30)90U10 254 272 306 387 - 3.0

(PHB70PCL30)80U20 249 271 392 691 - 7.2

(PHB70PCL30)70U30 265 239a 279 391 696 11.8

The Ton showed an increase of about 10°C with increased ulva content for

both formulations.

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180


Figure 3.67 shows the DSC traces for the PHBPCL/Ulva composites.

Figure 3.67 DSC Traces for the PHBPCL/Ulva. Composites.

The melting peak of PCL material was around 60°C which showed a

decrease in its intensity when PHB/PCL ratio was modified.

Sharp double melting peaks, typical of PHB material, were present around

at 170°C in blend (PHB80PCL20)90U10.

Table 3.51 shows the thermodynamic properties for the PHBPCL/Ulva

composites.

Results

181

Table 3.51 Thermodynamic Properties of the PHBPCL/Ulva Composites.

Sample Tm1 ∆Hm1 Tm2 ∆Hm2 Tm3 ∆Hm3

(°C) (J/g) (°C) (J/g) (°C) (J/g)

PHBPCL(80/20)90U10 56.43 21.21 166.26 -37.04 173.83 41.42

PHBPCL(80/20)70U30 56.30 7.02 164.03 18.93 173.04 27.72

PHBPCL(70/30)80U20 56.32 11.62 164.48 21.70 172.75 21.74

PHBPCL(70/30)70U30 56.91 10.14 164.68 16.08 173.63 20.45

Increasing the ulva amount, the PCL melting temperature remained

constant for all compositions, while the melting henthalpies decrease with the

ulva content werease. The ulva fibers make polymeric chains less movable

respect to the pristine polymers, so it is necessary a minor quantity of energy

to melt the composite materials.

Results

182


After conditioning (50 % RH), selected PHBPCL/Ulva specimens were

analyzed for their mechanical properties.

Data are reported in Table 3.52, while Figure 3.68 shows the trend of these

properties for the formulations containing a weight ratio 80/20 and 70/30 for

the polymers PHB and PCL and an ulva content from 10 to 30 percent.

Table 3.52 Mechanical Properties for the PHBPCL/Ulva Composites.


(%) (%) (MPa)

PHBPCL(80/20)90U10 3.4 0.3 22.8 0.8 1795.1 129

PHBPCL(80/20)80U20 2.8 0.3 13.0 2.2 1589.8 120

PHBPCL(80/20)70U30 1.6 0.4 12.8 2.8 1496.9 178

PHBPCL(70/30)90U10 4.1 0.4 17.9 1.7 1343.8 93

PHBPCL(70/30)80U20 3.5 0.4 17.4 2.1 1527.5 119

PHBPCL(70/30)70U30 2.7 0.3 16.2 1.1 1482.3 97

Formulations containing PHBPCL weight ratio 80/20 and 70/30 loaded

with ulva, showed small values for the elongation at break (EL) which

showed a decrease with increased algal content (Table 3.52).

So the produced composites resulted more fragile compared to the

PHBPCL ones characterized by the same weight ratio between the two

polymeric materials.

Young Modulus (YM) and the Ultimate Tensile Strength (UTS) with

decreased values showed that they were higher than that obtained for the

formulations PHBPCL without ulva.

So a variations in algal content had an impact on the YM of the composite.

Results

183

The effect on UTS was evident for all formulations as indicated from the

high values in Table 3.52.

(a) (b)

Figure 3.68 Young Modulus, Elongation at Break, Ultimate Tensile

Strength for the PHB/PCL (a) and PHBPCL/Ulva (b)

Composites.

3.8.1.8 Composites based on Hydrolene/Ground Rice


The SEM photomicrographs for the hydrolene (LFT) blends containing 30

% (a) and 50 % (b) of ground rice (FR) as natural filler, are shown in Figure

3.69.

(a) (b)

(a) (b)

Figure 3.69 SEM Photomicrographs of LFTFR30-1700X (a), and

LFTFR50-1700X (b) Composites.

Results

184

Fibers were well distributed throughout the matrix and exhibited

considerable cohesion with the polymer. The smooth, flexible, strong blends

showed the presence of regions with fiber aggregates, that partially filled the

ground rice inconsistencies: infact some of them were still evident in the

matrix.


Figure 3.70 shows the TGA (a) and DTGA (b) traces for the selected

compositions of LFTFR 90/10, 70/30, 60/40, 50/50, 40/60 composites and for

the pristine materials.

(a) (b)

Figure 3.70 TGA (a) and DTGA (b) Traces of the LFTFR Composites.

LFTFR composites showed at least five weight loss steps. The first one

corresponded to the humidity loss and it was connected with the increasing of

the ground rice amount, as this material retains a fairly high quantity of water

even after prolonged drying. It occurred in the temperature range of 25°C-

100°C with corresponding weight losses of 0.5 % for LFTFR10, 0.13 % for

LFTFR30, 0.3 % for LFTFR40, 1.5 % for LFTFR50 and 0.8 % for

LFTFR60.

Results

185

The second step was in the temperature range of 100°C-270°C and it

represented the pyrolysis of some additives (1.24 %) contained in the

Hydrolene.

The weight losses were 22.7 % for LFTFR10, 19 % for LFTFR30, 10.4 %

for LFTFR40, 11.2 % for LFTFR50 and 8.5 % for LFTFR60.

All compositions, except LFTFR10, showed a shoulder at the beginning of

the second peak, that felt down in the temperature range of 100°C-260°C.

The third and the fourth overlapped peaks represented the main

degradation effect and they occurred in the temperature range of 270°C-

410°C. The weight losses were 58.1 % for LFTFR10, 60.4 % for LFTFR30,

49.4 % for LFTFR40, 48.7 % for LFTFR50 and 55.5 % for LFTFR60.

The maximum degradation peak assumed a constant value for an high

organic material (content higher than 40 %) amount in the composite.

The fifth peak occurred in the temperature range of 410°C-490°C and the

corresponding weight losses were 12.5 % for LFTFR10, 7.7 % for LFTFR30,

15.0 % for LFTFR40, 11.4 % for LFTFR50 and 11.7 % for LFTFR60.

The residue recovered at 600°C presented high values connected with the

additives amount contained in LFT polymer, that didn’t decompose at the

experiment temperature. The values were 4.9 % for LFTFR10, 6.9 % for

LFTFR30, 10.3 % for LFTFR40, 9.7 % for LFTFR50 and 12.3 % for

LFTFR60.

The DTGA trend (Fig.3.68b) is more clearer when the ground rice amount

is higher than 50 % respect to the same type of composites where the ground

rice was present in the quantity of 10-30 %.

Results

186

Table 3.53 reports the thermal properties of the LFTFR composites.

Table 3.53 Thermal Properties of the LFTFR Composites.

Sample Ton Tp1 Tp2 Tp3 Tp4 Tp5 Tp6 R600

(°C) (°C) (°C) (°C) (°C) (°C) (°C) (%)

LFTFR10 234 280 349 436 - - - 4.90

LFTFR30 236 208 329 426 441 - - 6.85

LFTFR40 282 256 307 376 433 454 468 10.3

LFTFR50 277 245 304 362 426 - - 9.65

LFTFR60 278 244 307 372 424 - - 12.30

The onset temperature increased about 30°C with the ground rice

percentage, so the presence of the filler inside the composite made higher the

thermal stability of the material.


Figure 3.71 shows the DSC traces for the composites based on hydrolene

and ground rice while Table 3.54 shows the thermodynamic parameters.

Figure 3.71 DSC Traces of the LFTFR Composites.

Results

187

Table 3.54 Thermodynamic Parameters of the LFTFR Composites.

Sample Tg Tm ∆Hm

(°C) (°C) (J/g)

LFTFR10 55.8 175.2 11.17

LFTFR20 51.05 175.6 13.41

LFTFR30 51.5 180.54 7.48

LFTFR40 56.9 180.1 9.49

LFTFR50 47.8 187.49 4.24

LFTFR60 65.3 181.44 5.79

Melting heat ( ∆Hm ) showed small values for high percentages of ground

rice (50-60 %).

The glass transition temperature (Tg) was around to the value of the

pristine LFT. The ground rice addition decreased the amorphous behaviour of

the polymeric matrix: LFT chains became more movable so the material was

more easily processable.

Results

188

3.6.1.9 Composites based on LFT/FR/CaCO3


Figure 3.72 shows the SEM photomicrographs for the composite

LFTFR40 containing CaCO3.in the weight ratio 5 % (a) and 25 % (b).

(a) (b)

Figure 3.72 SEM Photomicrographs for LFTFR40CaCO35-450X (a), and

LFTFR40CaCO325-450X (b) Composites.

Calcium carbonate addition promotes a good adhesion between the

polymeric matrix (LFT) and the ground rice (FR).

The composite containing CaCO3 in the weight ratio 5 % presents

dominions characterized by different dimensions of the ground rice granules.

As in the hydrolene polymeric matrix, some holes are evident.


Figure 3.73 shows the TGA (a) and DTGA (b) traces comprised in the

temperature range 30°C-600°C for the composites containing

LFT/FR/CaCO3 in the weight ratio 50/40/10, 35/40/25, 25/40/35.

Results

189

Increasing the CaCO3 amount, these composites start to decompose at

higher temperature compared to the pristine materials and the formulation

LFTFR40.

Six decomposition peaks are evident, between which, the maximum

thermal degradation one is in the temperature range of 258°C-341°C for

LFTFR40C10, 251°C-340°C for LFTFR40C25 and 196°C-400°C for

LFTFR40C35 with a corresponding weight losses of 38 % for the first, 36.5

% for the second and 44.6 % for the third one. It doesn’t change in intensity

by adding inert material.

This is the third effect while the first peak, connected with the moisture

and volatiles elimination and the second connected with the pyrolysis of

some material components, felt down in the temperature range of 25°C-

100°C and 100°C-196°C. The relative weight losses were 0.6 %, 0.74 %,

0.86 % in the first case and 11.6 %, 8.4 %, 2.1 % in the second one.

The third peak presents a shoulder that decreases in intensity and

comprises between 340°C-400°C for LFTFR40C10, 340°C-396°C for

LFTFR40C25 and 340°C-423°C for LFTFR40C35, with weight losses of

19.6 %, 14.9 % and 5.41 %.

The weight loss steps at temperature superior at 400°C were connected

with the degradation of some inert material components. The percentages

were 5.2 % for LFTFR40C10, 6.5 % for LFTFR40C25, 6.4 % for

LFTFR40C35.

The residue recovered at 600°C shows increased values with CaCO3

amount increase, as this material doesn’t decompose at the thermogravimetric

experiment temperature. The relative weight losses were 19.7 % for

LFTFR40C10, 20.2 % for LFTFR40C25, 26.6 % for LFTFR40C35.

The DTGA trend (Fig. 3.72b) showed traces overlapping in a temperature

ranges of 100°C-300°C and 350°C–450°C. Calcium carbonate refrains

decomposition of the composite containing 40 % of ground rice as seen from

Results

190

Ton formulations (Table 3.55). The degradation process appears to be

controlled by the interactions between CaCO3, the polymeric matrix and the

ground rice, that were very strong.

In Table 3.55 are collected the thermal parameters for the LFT/FR/CaCO3

composites.

(a) (b)

Figure 3.73 TGA (a) and DTGA (b) Traces of LFT/FR/CaCO3 Composites

and the Pristine Materials.

Table 3.55 Thermal Parameters of the LFT/FR/CaCO3 Composites.


(°C) (°C) (°C) (°C) (°C) (°C) (%)

LFTFR40C10 243 245 302 353 429 691 14.2

LFTFR40C25 278 218 301 350 432 699 20.2

LFTFR40C35 275 304 422 545 699 778 26.8

Results

191


Figure 3.74 shows the DSC traces for the LFT/FR/CaCO3 composites,

while in Table 3.56 are collected the relative thermodynamic parameters.

Figure 3.74 DSC Traces of the LFT/FR/CaCO3 Composites.

Table 3.56 Thermodynamic Parameters of the LFT/FR/CaCO3

Composites.

Sample Tg Tm ∆Hm

(°C) (°C) (J/g)

LFTFR40C5 54.8 180.33 8.69

LFTFR40C10 55.2 179.95 7.18

LFTFR40C15 58.1 180.85 6.75

LFTFR40C20 41.13 179.81 5.37

LFTFR40C25 39.71 180.15 5.50

LFTFR40C30 - 188.12 2.65

LFTFR40C35 61.21 183.34 3.97

The amorphous part of the polymeric matrix is increased when a 20-25 %

of CaCO3 was added in the formulation and the relevant glass transition

temperature (Tg) drops down to minimum values.

Results

192

The melting temperature (Tm) shows values similar to that of composites

based on PHB and useful to produce them by compression moulding.

3.6.1.10 Composites based on LFT/FR/CaCO3/CaSO4


Figure 3.75 shows the SEM photomicrograph for the composite

LFTFR40CaCO3 containing 5 % of CaSO4.

Figure 3.75 SEM Photomicrograph of the LFTFR40CaCO3_CaSO45-500X

Composite.

Also the CaSO4 addition improved the adhesion between the polymer LFT

and the filler FR, creating a drastic decrease in the number of inconsistencies.

The laminates surface appeared to be smooth and rigid.

Results

193


Figure 3.76 shows the TGA (a) and DTGA (b) traces for the composites

containing LFT/FR/CaCO3/CaSO4 in the weight ratio 50/40/5/5, 40/40/10/10

and 30/40/15/15 in the temperature range between 30°C and 800°C.

The addition of CaSO4 to the blend leads to an increase of the degradation

temperature, the number of peaks and the residue recovered at 800°C for all

formulations.

LFTFR40C10G10 and LFTFR30C15G15, after humidity loss, that occurs

in the temperature range of 25°C-100°C, display the maximum degradation

peak at 270°C-280°C temperature range. The corresponding weight losses

were 1.3 % for the first formulation and 0.96 % for the second one.

Below 250°C, the DTGA traces show small thermal effects that were

correlated with the calcium sulphate thermal decomposition.

The residue recovered at 600°C, had a drastic decrease (7.7 %) for the

formulation containing 10 % weight ratio of CaSO4, while the values were

19.8 % for LFTFR40C10G5 and 35.1 % for LFTFR40C10G15. The

increased trend depends on the CaSO4 amount increase which doesn’t

decompose at temperature at which the experiment is conducted.

(a) (b)

Figure 3.76 TGA (a) and DTGA (b) Traces for LFT/FR/CaCO3/CaSO4

Composites.

Results

194

In Table 3.57 are collected the thermal parameters of the

LFT/FR/CaCO3/CaSO4 composites.

Table 3.57 Thermogravimetric Data of the LFT/FR/CaCO3/CaSO4

Composites.


(°C) (°C) (°C) (°C) (°C) (°C) (%)

AC5G5 266 248 303 354 427 - 19.8

AC10G10 275 227 303 354 427 687 7.7

AC15G15 274 223 305 345 429 689 35.1

A = Serie Basata su LFT/FR40.

The thermal stability remains constant for all formulations, as seen from

the Ton data in Table 3.57, while the formulation containing both 10 % of

CaSO4 and CaCO3 appears to be more thermally stable (Ton= 275°C)

compared to the same formulation without calcium sulphate (Ton= 243°C).

3.6.1.11 Composites based on LFT/PHB/PFc/CaCO3/CaSO4


Figure 3.77 shows the SEM photomicrographs for the composites

containing CaCO3 (30 % and 55 %), PHB (5 % and 30 %) and a constant

weight ratio (10 %) of LFT and CaSO4.

The holes in the polymeric matrix have small dimensions, when the

calcium carbonate amount increases.

Results

195

(a) (b)

Figure 3.77 SEM Photomicrographs of LFT10/PHB30/PFc20/C30/G10-

80X (a) and LFT10/PHB5/PFc20/C55/G10-50X (b)

Composites.

Results

196


Figure 3.78 shows the TGA (a) and DTGA (b) traces of the composites

containing LFT/PHB/PFc/CaCO3/CaSO4 in the weight ratio 5/20/20/45/10,

10/30/20/30/10 and 10/5/20/55/10 in a temperature range between 30°C and

800°C. PFc is a mixture consisting in chaff and farinaccio in the weight ratio

80/20.

(a) (b)

Figure 3.78 TGA (a) and DTGA (b) Traces of the

LFT/PHB/PFc/CaCO3/CaSO4 Blends.

After humidity and volatiles loss that occurred in the temperature range of

25°C-100°C, these samples started to degrade in a temperature range around

at 220–230°C.

The DTGA traces (Fig. 3.78b) showed three decomposition peaks and the

residue recovered at 800°C tend to increase with the increasing of the

inorganic components content. The traces are overlapped between 0 and

300°C.

The decrease of inorganic components addition tends to decrease the

natural material degradation. Higher temperatures are infact recorded for the

chaff and flour in the composites with respect to the pristine organic

compounds.

Results

197

In Table 3.58 are collected the thermal parameters of the blends based on

LFT/PHB/PFc/CaCO3/CaSO4.

Table 3.58 Thermal Parameters of the LFT/PHB/PFc/CaCO3/CaSO4

Blends.


(°C) (°C) (°C) (°C) (%)

LFT10PHB30PFc20C30G10 230 250 315 726 27.6

LFT5PHB20PFc20C45G10 230 248 318 727 34.8

LFT10PHB5PFc20C55G10 223 241 311 728 45.2

The increased amount of the two polymers and CaCO3 hadn’t impact on

the Ton values, which remained constant for all formulations.

The recovered residue at 600°C were 27.6 % for

LFT10PHB30PFc20C30G10, 34.8 % for LFT5PHB20PFc20C45G10, 45.2 %

for LFT10PHB5PFc20C55G10, showing an increased trend with the increase

of the inorganic part in the formulation.

3.9 Conclusions

The density and fragility for the produced composites were identified and

natural biodegradable materials such as ground rices or algal biomasses were

selected with the aim to improve the eco-compatibility of the final product.

Inert inorganic materials, such as CaCO3 and CaSO4, were used to confer

an high density to the composites.

The selected polymeric matrix was Hydrolene (PVA) in form of granules

and aqueous solution (30 % in weight) with good ligand properties, solubility

and biodegradability in aqueous environment. PHB and PCL were utilized to

improve the composite degradation.

Results

199

The thermal characterization pointed out the possibility to process the

blends at high temperatures, so the selected formulations were processed by

means of a Braebender mixer in a first phase and the promising mixtures

were processed in a double screw extruder in a second phase.

Exceptions were the formulations with an high inorganic material content,

that were directly blended in a Turbo-Mixer followed by a compression

moulding step.

The results appeared to be good, as the obtained laminates were

consistent, fragile and they could reach the desired density.

Results

201

4 THE FOAMING AGENTS


202

Chemical foaming agents (CFAs), also known as blowing agents, are used

to produce foamed plastics in sheet or profile estrusion, injection and roto

moulding for a wide variety of applications.

This market is dominated by Asia (China in particular) with large volumes

going into low-end consumer goods and of the estimated 159 Ktons of them

for thermoplastics sold in 2005: 46 % used in China, 23 % in other Asian

countries, 17 % in Europe, 6 % in North America, 8 % in the rest of the

world. Global supply of foaming agents is dominated by Asian companies

and these products are predicted to grow 5.5 % AAGR through 2009. In

particular a growth of 8 % is predicted for China and 2-4 % for the other

regions.

A chemical foaming agent decomposes thermally into carbon dioxide and

nitrogen, that are liquids under the process pressure and they can mix with the

molten polymer. When a pressure drop occurs at the die or in the mould, these

two gases expand into bubbles within the polymer matrix. The polymer cools

and the bubbles freeze, creating a foamed plastic.

The CFAs have also a nucleation effect, that results in a reduced cell size,

when they are used in combination with physical blowing agents such as

pentanes or other hydrocarbons.

Resin technology plays an important role in foaming: amorphous resins

with highly branched chains and high melt strength are easier to foam than

crystalline, linear, low melt strength one.

The most widely used type of chemical foaming agent is

azodicarbonamide (ADCA) that is an exothermic CFA and it decomposes

into nitrogen. On the market, we can find also endothermic agents that are

complicated formulations based on a variety of chemistries such as sodium

bicarbonate/citric acid derivatives, that release carbon dioxide. About 88 % of

global CFA volume is ADCA, with 5 % in the endothermic forms and 7 % in

various other types, including 4,4-oxybis benzene sulphonylhydrazide

Results

203

(OBSH).

The European Commission’s Directive 2004/1/EC suspends the use of

ADCA in food contact materials, because of this product was used in sealing

gasket for the lids of glass jars and bottles, such as baby food, becouse of this

product decomposes into toxic by-products.

The main applications are in the automotive sector, (low-density

polypropylene foam), electronics (housings for televisions, computers,

printers), packaging (new PLA biopolymer resins), building and construction

(fencing, decking, window and door profiles, wood plastic composites), the

nucleation in direct gas extrusion systems, that use gases such as nitrogen or

isopentane to make foamed polystyrene and polyethylene. It is important also

the new production of high-temperature resins such as Foamazol TM X0-230

formulated for the use in high temperature polycarbonate foaming

applications such as structural foam moulding, injection moulding and

extrusion. Another example is Hydrocerol XH designed for use with resins

based on polycarbonate and nylons that require extra high processing

temperatures over 500°C, roto-moulding that uses azodicarbonamide powders

along with resins in powder form(190).

The main features of these products are the use in injection, rotational and

structural foam moulding, the exceeded performance levels of currently

available CFA’s, the consistent results, the uniform cell structures, the wide

range of activity levels and gas yields, the hybrid endo/exothermic grades in a

single pellet and the elimination of sink marks.

The benefits are the uniform weight reductions, the fast degassing, the

lower production costs and the lower raw material usage, the achieved

superior surface characteristics, the enhanced physical properties and the

increased “strength-to-weight” ratio(193,194).

For many years, some foaming agents such as thermoplastic micro-spheres

(TMS), namely Expancel Micro-spheres, were successfully used providing a


204

consistent, tight, uniform cell structure in the polymer matrix that is necessary

to maintain the achieved densities and the mechanical properties.

Wood Plastic Composites (WPC) consist of a mixture of wood flour bound

into plastic matrices. Most commonly used thermoplastic resins in WPC

include polypropylene (PP), polyethylene (PE), acrylonitrile butadiene

styrene (ABS), styrene acrylonitrile (SAN), acrylonitrile styrene acrylonitrile

(ASA), polyvinyl chloride (PVC) or polystyrene (PS). Foaming agents grades

such as SAFTEC TFPE-504 are preferred for use with wood composites(192).

Thermoplastic Expancel® Micro-spheres are essentially hollow balloons

consisting of a thermoplastic outer shell encapsulating hydrocarbons as a

blowing agent. The particle size of the micro-spheres ranges from 10–32

microns diameter in their unexpanded form. On applying heat, the

thermoplastic shell softens, the hydrocarbon gas pressure inside increases,

and the micro-spheres will expand approximately four times in diameter

compared to their original sizes(191).

The foaming agents and the additives are modifying their chemistries to

support technologies involving both microcellular applications and foamed

wood/plastic composite technology. This consists in a combination of a range

of polymers, wood/cellulosic fibers and special additives to produce

applications that include floor decking, pallets, roofing tiles and mouldings.

So many companies have developed their own technologies to produce

microcellular foam structures.

For example Collins & Aikaman’s Intellimond is a process control system

that achieves Class A surface, decreases the part density and reduces the cycle

times, while the Sulzer Chemtech process is a plastic processing mixers for

foam applications utilizing an unique intersecting channel design.

This technology cross-mixes and homogenizes polymers and additives

very efficiently. The latest technologies for microcellular foaming use a new

compact gas counter pressure module(192)..

Results

205

EPI is marketing patented endothermic (EPIcor), exothermic (EPIcell),

and exo-endo (POLYcor) CFAs with special emphasis on its endothermic line

of CFAs. These latter products are more versatile than the exothermic ones

and they can be used in numerous new applications and products that

currently do not use any type of CFAs(193).

Two-step synthesis for a new liquid foaming agent based on dodecanol

phthalic anhydride anionic salt temperature resistant foam flooding, are used

for the technical requirements of the process.

The foaming agents (lauryl alcohol and phathalic anhydride) are the

starting raw materials and they are involved in the esterification and the

synthesis. Rose-Mile with Waring Blender mixing and foaming agents on

liquid foam system and its salt, anti-oil performance evaluation were studied

showing that the foaming agent (SDS and ABS-keung) on the oil sands was

not nearly adsorption.

A sulphate anionic surfactant can maintain its main chemical features at

high temperatures sustaining a good foaming capacity and decomposition

temperature above 300°C. In cyclic steam stimulation or steam flooding, the

foam can be inhibited by adding gas channelling and regulating injection

profile, improve the efficiency of gas injection to extend the cycle, and

increase the oil production.

The foaming agent has a surfactant nature and it consists in a variety of

chemical products that are mainly used for the tertiary oil recovery in the

mining bubble displacement.

The foam components will be in proportion mixed with water (or other

material), and the gas at the same time by a certain percentage or indirect

injection into the can.

Foam used in oil recovery is a relatively new technology, and so it has a

huge market potential, a displacement effect and a swept volume that is much

larger than a simple injection of water and polymer.


206

Application of foam flooding has achieved good results. The products can

be used alone giving better results and better performance of flooding to

maximize the synergy effect(197).

The specialists of LLC Stroy-Beton present a new protein foaming agent

for light weight cellular concrete (foamed concrete) GreenFroth.

This product contains natural surfactants that are mixed with organic raw

materials, which work in synergy with them. GreenFroth shows an increased

ratio and an higher resistance compared to the other imported foaming agents

and synthetic ones.

Consequently it is possible to reduce the consumption of the foaming agent

on each cubic meter of foam concrete approximately to 45 % that adds to the

quality and the strength of the produced foam concrete. The flexible system

of deliveries was carried out to have this foaming agent always in store and to

dispatch customers without any delays(195).

GreenFroth allows to produce foam concrete of density ranging from 200

up to 1600 kg/m3. In this case, the foaming agent is a protein that contains

natural surfactants mixed with organic raw materials. For this reason it has a

pleasant odour and its main qualities include a higher resistance of foam and

better characteristics of the foaming process in comparison with other protein

foaming agents.

GreenFroth is produced in a special developed foam generator Fomm-

PGM. The foam is added into main cement mixture as an homogeneous

dispersion, during the mixing process, in a mixer. Stabilising components

contained in GreenFroth provide keeping pores of foam concrete for the

whole period of its processing. The expected characteristics were the

humidity resistance, the high strength and the ecological friendliness.

In comparison to the other protein foaming agents the required amount of

GreenFroth is 45 % less on each cubic meter of foam concrete

GreenFroth is used for foam concrete production of normal and light

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207

filters. Depending on the main formula it is possible to produce mixtures of

density from 200 kg/m3 to 1600 kg/m3, while a density less than 600 kg/dm3

requires special composition, production and usage.

The foaming agent is provided as a concentrate and it is needed to prepare

2,5 % water solution mixture for producing foam. After that the generator

produces a foam of density 50 gr/l: this means that it is recommended to be

applied on 20 % ratio of foaming, at 2,5 % initial water solution mixture. So a

less foam amount is needed and a concrete foam of higher strength(195) is

produced.

The foam generator allows for control of gypsum board void structure

regulating the respective amounts of the two soap streams. The first is a

standard board soap, such as alkyl chain length 8-12 carbon length and ethoxy

group chain length of 1-4 units, while the second is an unethoxylated one with

an alkyl chain length of 6-16 carbon units that can be branched or un-

branched.

In addition to regulate the ratio of the two soaps, it can be used a

predominant amount of the alkyl sulphate oligomer that is a foaming agent

forming unstable foam voids in the gypsum slurry.

The first soap is represented by the formula: CH3 (CH2)X CH2 (OCH2

CH2)Y OSO3--Me+ where X ranges from 2 to 20, Y ranges from 0 to 10 with a

major portion of Y being greater than 0 and M is a cation, while the second

soap is represented by the formula: R OSO3--Me+ where R is an alkyl group

containing 2 to 20 carbon atoms and M is a cation. More preferably X ranges

from 4 to 16, Y ranges from 1 to 6 and R is an alkyl radical containing 4 to 16

carbon atoms. In the best mode, X ranges from 6 to 12, Y ranges from 2 to 4

and R is an alkyl radical containing 6 to 12 carbon atoms.

Either cation is selected from the group consisting of sodium, potassium,

magnesium, ammonium, quaternary ammonium and their mixtures.


208

Preferably, each cation is either sodium or ammonium. The ratio by weight

of the first foaming agent to the second foaming agent generally is less than

50/50. Typically, it ranges from 50/50 to 0/100, but the best ratio ranges from

40/60 to 10/90(196).

FascomTM Chemical Foaming Agents are a range of polymer additives of

significant technical importance for providing production, economic,

environmental and physical improvements when processing a wide range of

polymers.

FA’s are different than other classes of polymer additives and they are

designed to decompose during normal processing of that polymer at elevated

temperatures (>150ºC). They release an high volume of gas that can be

trapped within the polymer melt creating a cellular or a foamed structure.

By forming a cellular structure the initial benefit created is a reduction in

specific gravity which affords a number of potential properties including the

easier handling, the reduced polymer requirement, the improved product

dimensions, the improved insulation, the cushioning, the design aesthetics.

WSL have an extensive range of products and chemistries designed to

cover numerous applications, processing methods and temperatures.

Typical applications include; uPVC foamed profile, pipe and sheet, PVC

plastisols for flooring, wall covering, belting and artificial leather,

polyolefines for extrusion, injection moulding and rotational moulding and

rubber for extrusion and moulding operations(198).

OnCap™ has formulated CFA products that are available in concentrated

powder or pellet form in carrier systems compatible with most application

resins. CFA concentrates are usually used in very small amounts (0.1-1.0 %)

even if some applications may require higher addition rates up to 6 % or 8 %.

They are easy to handle and feed using the conventional feeding

equipment used in polymer processing.

CFAs find use across a wide range of market applications, including

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209

packaging, transportation, medical devices, building and construction, wire

and cable, toys and other consumer goods, industrial goods, and wood/plastic

composites.

PolyOne offers a one-stop source of colour and additive concentrates,

colour and additive systems, and associated technology and support services.

It has than 20 manufacturing locations in North America, Europe and Asia,

with colour labs, design centers and sales offices located around the

world(199).

Table 3.59 reports the main foaming agents produced by Alqemia

Group(200), while Table 3.60 shows the relative product description.

Table 3.59 Main Foaming Agents by Alqemia Group(200).

Product Reaction Processing Active Add. Level

Type Temp (°C) Conc (%) (%)

FM0N830LD Exothermic 210-240 35 2-35





FM0N880LD Endothermic 170-280 40 0.5-4

FM0D410LD Endothermic 170-280 70 0.5-2

FM0D890LD Endothermic 170-240 40 0.5-4

FM0N990LD Exo/Endo 170-240 30 0.5-4


210

Table 3.60 Product Description(200).

Product Product Description

FM0N830LD ADCA suitable for PE including cross linked

foams

FM0N840LD ADCA affering accelerated foaming for PE

including cross linked foams

FM0N850LD ADCA designed for high output/high shear

processing

FM0N860LD ADCA with accelerated foaming designed for

extrusion and injection moulding

FM0N870LD ADCA with highly accelerated foaming designed

for extrusion and injection moulding

FM0N880LD Endothermic system with good nucleation for

injection moulding of polyolefins

FM0D410LD Endothermic system with good nucleation

suitable for extrusion and injection moulding of

polyolefins

FM0D890LD Endothermic system with good nucleation

suitable for extrusion and injection moulding

FM0N990LD Combination system allowing good gas yield and

broad process window

MILLIFOAM is a gypsum foaming agent that is optimized by selecting the

chain length, the degree of ethoxylation and the cation. The selected foam

stabilizers contribute to the formation of a strong low density gypsum board.

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211

MILLIFOAM helps to stabilize gypsum plaste board by the following

phenomena:

1. the repulsion of surfactant head groups retains the thickness of

the lamellar and it reduces the bubble film drainage.

2. the rapid diffusion of the surfactant to the expanded surface

reinforces the film thickness, preventing the natural deformation of the

film.

3. the densely packed surfactant film can reduce the diffusion of

the gas through the liquid interface and it can help prevent the bubble

destruction.

The advantages are the greater consistency and the product quality, the

small bubble size, the creation and the stabilization of the air bubbles within

gypsum slurry, the regular foam structures, the avoiding areas of weakness

and the reduced-strength board, the avoiding unsightly air voids at the edge of

the sheets, the avoiding bubbles that cause paper bonding problems or

blistering. The application dosage (0.01 and 0.05 % by weight of gypsum)

depends on the sources and the manufacturing plant methods(201).

The product range is in Table 3.61.

Table 3.61 MILLIFOAM Product Range(201).

Products Description Total Active Cation Foam

Ion Active Mater (%) Stabilizer

MILLIFOAM B Alkyl ether 32 Na+ -

Sulphate

MILLIFOAM C Alkyl ether 31 Na+ Yes

Sulphate

MILLIFOAM D Alkyl ether 75 NH4+ Yes

Sulphate


212

AQF-2TM foaming agent is used to stabilize the gas and liquid levels of

foamed fracturing fluids. The temperatures are between 24°C and 93°C and

the typical agent concentrations are 2 to 5 gal/Mgal of fracturing fluid.

At temperatures between 24°C and 149°C, typical agent concentrations

are 6 to 10 gal/Mgal of fracturing fluid.

The oily surfaces act as defoaming agents in many foamed systems, and

most foaming agents are oil-intolerant. However, AQF-2 foaming agent is

less adversely affected by the presence of oil. In addition, this agent can

slightly counteract the defoaming tendencies of some materials, such as

SandWedge® treatment(202).

Counter grades for foaming agents are used in the production, such as

Porofor ADC/M-C1 (Bayer); Porofor ADC/F-C2 (Bayer); Porofor ADC/L-

C2 (Bayer); Porofor ADC/S-C2 (Bayer); Azobul F1 and Azobul B (Arkema);

ADC-5 (China); Porofor CHZ-21.

Being the counter grades of the abovementioned brands Cellcom foaming

agents have more advantages taking into consideration the quality and the

price ratio(203).

The addition of about 3 % of a mixture containing 70 % DIACID 1550

dicarboxilic acid and 30 % Na-DDBS sulfonate soap to a typical pigmented

size press solution produces a density reduction of from about 1.1 gm/cc to

about 0.13 gm/cc using an Oakes foam generator. The methods currently

being used to obtain low foam densities include an increase of the

consumption of foaming agent or an utilize of a more active one, both of

which tend to increase costs. The synergistic interaction of DIACID 1550

dicarboxylic acid, that is an emulsifying agent, with the sodium salt of an

alkyl benzene sulfonate that is a detergent surfactant, produced a lower

density foam than either component used individually.

The paper industry uses this mixture as a coating or surface size

application, the textile industry uses it in the surface treatment of fabrics

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213

while the plastics and carpeting industries use the mixture for producing voids

in solid materials(204).

DIACID 1550 dicarboxylic acid is a product of Westvaco

Corporation and it contains two major isomers (Fig 3.79):

Figure 3.79 DIACID 1550 Dicarboxylic Acid Isomers.

Na-DDBS is the most typical and common alkylbenzene sulfonate, a

detergent surfactant from the general class of alkylarylsulfonate soaps

represented by the formula (Fig. 3.80):

Figure 3.80 Alkylarylsulfonate Soap.

where M is sodium or potassium and R is dodecyl.

The trade name LithoFoam includes several foaming agents, that are

protein based on enzymatic active components, developed especially for the

building material industry. Diluted in water and processed in a foam generator

with compressed air, they produce a very fine and stable high quality foam.

Standard protein based on foaming agents, are made with protein

hydrolyzate from animal proteins out of horn, blood, bones of cows, pigs and

other remainders of animal carcasses. This leads on the one hand to a very


214

intense stench of such foaming agents and on the other hand to a broad range

of molecular weight of the proteins because the raw materials are always

changing(205). The new innovative foaming agent technology created by Dr.

Lucà und Partner, however, is not based on the unattractive protein hydrolysis

but on a biotechnological procedure. LithoFoam products have a neutral,

technical odour and they are adjustable to every need. This goal was reached

using right concentrations for the active enzymes and proteins (3-10 %). As

less superfluous external material that could disturb the properties of the

concrete mix can be inserted in the foam. The low ratio of active agents is

made possible through a special process using nanotechnology, developed by

Dr. Lucà und Partner. So LithoFoam foaming agents can be offered at prices

far below those of competitors. The advantages are the products variety, the

improved silicone oil and frost resistance, the anti bacterial properties

(effective against mildew). The foam gross density adjustable to 20-180

kg/m³ and the high efficiency are important parameters for roofing, flooring,

block production and casting in situ walls(205).

CELOGEN products are chemical foaming agents (CFAs) or chemical

blowing agents (CBAs) that are used to impart a cellular structure to foam

plastics, rubber, and thermoset resins by releasing nitrogen gas during the

processing. They are available in a variety of particle sizes to optimize cell

size, and they can be cured by using liquid cure media (LCM), hot air, fluid

bed or microwaves. They are effective in natural, butyl, EDPM, neoprene,

nitrile, silicone and SBR rubbers.

Acticell activator enhances Celogen® foaming agent performance over a

wide range of temperatures. Manufacturers can use it to reduce the energy

costs by processing at lower temperatures, or to improve the productivity at

the temperatures they're using now. This product is economical, can be

dispersed easily and it is compatible with NR, SBR, butyl, EPDM

(Royalene®) and Neoprene rubber formulations(206).

Results

215

5 EFFERVESCENT MATERIALS


216

The chemical reaction that creates the fizz in effervescent bath and shower

products is quite simple and it consists in an acid neutralization with a

carbonate salt with carbon dioxide gas realising, the salt of the acid and water

production.

Figure 3.79 shows the scheme of the effervescent reaction:

Acid + Carbonate Salt_CO2_ + Acid Salt + H20

Ex: Citric Acid + 3NaHCO3_3CO2_ + Na3Citrate + 3H20

Figure 3.79 Effervescent Reaction Scheme.

A small amount of water is needed to start the reaction, becouse of without

water, neither the acid nor the carbonate can dissociate, but when the reaction

is started, it generates more water.

All raw materials used in an effervescent product must be anhydrous and

they must be stored in manufacturing environments where they must also be

designed to maintain dryness.

Typically these facilities are dehumidified to less than 10 % RH. To

protect them from the ambient humidity, the effervescent products are usually

packaged in high barrier foil and/or polymer films or in heavy-wall jars that

contain desiccant packs(207,209,210,211,231).

The raw materials for effervescent product are(209):

1. Sodium Carbonate: available as an anhydrous form and as a

monohydrate or a decahydrate. It adsorbs moisture and it is water-

soluble.

2. Sodium bicarbonate is a white crystalline powder. It is

available in five particle-size grades from fine powders to free flowing

granules.

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217

3. Citric acid: available abundantly, inexpensive, good solubility

in water and alcohol. It is available as fine granular, free flowing

powder forms of different particle sizes such as coarse, medium, fine.

4. Fumaric acid: available as a white granules or crystalline

powder. The solubility in water is reached using the form of salt such

as mono sodium or potassium fumarate.

The promotion of the effervescent reaction between citric acid and sodium

bicarbonate(217) creates a fine connected porous structure in polymer

membranes which were prepared by a novel microwave assisted effervescent

disintegrable reaction.

Other raw materials used in the effervescent reaction are tartaric, ascorbic,

malic, adipic, succinic and acetyl salycilic acids and their relative salts,

potassium carbonate and bicarbonate, sodium sesquiscarbonate, sodium

glycine, L-lysine, arginine, amorphous calcium carbonate(229).

Fragrances and essential oils (0.5 % and 3 %) are virtually always included

in these products providing a technical assistance in designing perfumes for

use in effervescent products.

The oil must be compatible with effervescent bases by avoiding materials

such as glycol solvents that may cause instability to occur by allowing partial

dissociation of the acid or carbonate(207).

Functional materials (1-2 %) such as freeze-dried aloe, chamomile extract

in oil, and even dried flower buds and bulk herbs can be introduced in the

formulation.

Also emollient materials such as squalane, vitamin E, almond oil and many

cosmetic esters are frequently incorporated, again, generally from 0.1 % to 2

%. Surfactants are used both as fragrance emulsifiers and as foamers.


218

In the first case, surfactants prevent the perfume oil from floating on the

water’s surface. Typical emulsifiers are PEG-30 castor oil, Polysorbate 80 or

85 and Laureth 4. The precise choice will depend on the HLB of the perfume

oil.

If surfactants are going to be used to create foam, special formulations are

required to achieve consumer acceptable performance. Polyquaternium 10

and PEG (0.2-4 %) can also be added to help modify skin feel and the feel of

the bath water. Binders such as sorbitol, lactose and maltodextrin (10-20 %)

are almost always needed to make good, solid effervescent tablets.

These formulations can also contain materials such as fumed silica,

calcium silicate, cornstarch, talc(207), that make more efficient the powders

flow preventing the sticking on the production equipment(211).

The production process of an effervescent product is a conventional solid

dosage form manufacturing(222) that considers its special characteristics.

To overcome the problem of the moisture is necessary that all machines

must allow for proper venting with air of a sufficiently low moisture content.

The tablets are compressed by an high speed rotary tablet presses(224) using

a dry method that consists in a direct compression or a roller compaction used

in the solid dosage forms.

There are two granulates methods that consist in making of wet

granulation using two separate granulation steps for the alkaline and the acid

components with a subsequent dry blending step. This can be done in a high

shear granulator, with subsequent drying, a single-pot or in a fluid bed spray

granulator.

Thiokol Corporation uses several thermal setting urethane and epoxy

slurry formulations in the production of rocket motors and pyrotechnic

devices used as liners that contain solids with thixotropic characteristics,

thermal resistance and inert behaviour.

Their application is accomplished by methods such as spraying or

Results

219

atomizing with centrifugal force (sling lining). The solids loading causes an

increase in the viscosity so that a diluent, such as ozone, toxic and/or

flammables solvents, is required in order to spray them(212,213).

Effervescent tablets, based on sugar alcohols(219) such as sylitol, erythritol,

mannitol, showed medicine and health care curative effect.

The patent number:200410021760.7. includes the effervescent tablets and

the effervescent granules. The sugar alcohol is a natural and healthy

sweetener, existing in some fruit or vegetable and it made from the sugar or

plant. It has an extremely low heat, it can only be absorbed partly or utilized

slowly in the body and it may cross through the cell membrane, offering

nutrition supplement and auxiliary medicine for diabetes patient.

Moreover sugar alcohol promotes the growth of the beneficial bacterium in

the body, maintaining the ecological balance of the intestines and it promotes

the liver glycogen to synthetic, improve liver function.

In the Chinese market, effervescent tablets are a novel, fashionable form of

a drug or health-care food that are raising bunches of light bubble in water

constantly and they have good sense organ effects and well received by

people, especially children. In addition effervescent tablets have a lot of

excellent characteristics such as the speed dissolution in water that is very

quick. When the tablets keep in touch with water, the sour and alkali happens

to react, producing a lot of carbon dioxide, fully dissolved in a short period of

time(217,219).

There is also a type of effervescent tablet based on pearl(214). This product

is a novel calcium supplement food, extracting from the natural concentrated

liquid of pearl with a patent technology. The tablets contain active calcium,

through a spray and a drying process to make powder and refined

meticulously with a number of specific materials. It can generate an

immediate gasification reaction as soon as it was meeting with water and a

wonderful phenomenon of bubbling appeared in the drinks cup. Moreover,


220

the product is rich in active calcium and aminoacids that are dissolved rapidly

and readily absorbed in the body.

The product causes no precipitation produced by the oxalic acid which

influencing the absorption of calcium as compared with plant foods; it does

not combine with phosphoric acid in the bone that is hard absorbable in the

body as compared with animal osseous calcium. Moreover it is more stable

than other effervescent product in which the only nutritive element is Vitamin

C, being easily destroyed through oxidation.

It also contains traces of zinc, copper, iron, manganese and selenium, 18

kinds of amino acids and taurine in addition to calcium.

An example of tablets is constituted by the LiFizz Strawberry Flavored

Effervescent Calcium Plus D tablets(215) that are used for acne, aging, healthy

skin, hair, nails, wrinkles. These tablets are unwrapped and a desiccant

protects the tablets from air and moisture, keeping them fresh.

For the same reason, a cap is designed with a spiral "shock absorber" to

help the reduction product damage to the unwrapped tablets and the carton is

designed with folded inner tabs to help secure the tube(216).

A new method of expanding plastic during moulding looks to change the

way plastic goods are manufactured in the future. By infusing microscopic

bubbles into the interior of plastic, MicroGREEN, an Arlington Washington

based firm, has developed a solid-state microcellular technology that

increases strength and more importantly, vastly reduces the use of plastic

source materials.

MicroGREEN’s patented technology, developed at the University of

Washington, promises to increase output while lowering material costs by up

75 % or more. The process can be tailored to each specific application and it

can be used with a variety of virgin and recycled plastics, such as PET and

even bio-plastics like PLA. The process does not chemically alter the plastic

so the end product can be recycled over and over again.

Results

221

The process that creates a naturally smooth outer surface, is lighter weight,

it has excellent insulating qualities and it requires less manufacturing(218).

DISINBIO(220) is a China s first instant-effervescent organic chlorine solid

disinfectant, characterized by its performance stability, quantity precision,

high efficiency broad-spectrum, minimizing corrosion while disinfecting

without leaving harmful residues. The main ingredients are sodium

dichloroisocyanurate, formally approved by the FDA and EPA for food,

medical equipment and drinking water disinfection. Other components are

sodium dichloroisocyanurate (DCCNa), potassium bromide (KBr), boric acid

(H3B03), potassium chloride (KCl), sodium chloride (NaCl), synergists,

decomposers, anti-interference agents, stabilizers. The formulation is

available in tablet, granule and powder form.

The benefits are the efficiency in killing bacteria, candida albicans, fungi

and bacterial spores, hepatitis virus, alternaria, bacillus subtilis, influenza

virus, HIV and other pathogenic micro-organisms.

The main applications are the use in medical and health care, in the anti-

epidemic (drinking water, tableware, fruits & vegetables, environment, public

utensils, etc), in the public and domestic areas, foodstuff (beverages),

livestock (fishery), aquaculture, in the industrial and agricultural production

purposes and areas where disinfection is needed. The advantages are the

germicidal effect, infact the instant effervescent in solid dosage forms allows

for the accurate quantity in usage, the safety for the users and the

environment, the stable performance with the resistance to the organic

materials, acid, alkali and other chemical properties, the minimum corrosion,

the versatility(220).

Calcium phosphate cements(221) (CPCs) are biocompatible and

osteoconductive materials used in dental, craniofacial and orthopaedic

applications. One of the most important advantages of these materials is their

replacement with bone followed by re-sorption.


222

A mixture of NaHCO3 and citric acid monohydrate was added to the

apatite cement component as an effervescent additive for producing

interconnected macro-pores into the cement matrix.

The obtained results showed that the addition of only 10 wt % of the

effervescent additive (based on the cement powder) to the CPC components

lead to producing about 20 V % macro-pores (with the size of 10 to 1000

mum) into the cement structure(221).

Effervescent creatine and creatine monohydrate are different chemical

states of the same molecule. EC is a zwitterion, meaning it has both a positive

and negative charge on it. Researchers claim that this form is absorbed faster

into the bloodstream. Following that logic, manufacturers of EC claim that

CM is not as well absorbed; therefore, EC is better than CM(223).

Chunthong et al(225) create a formulation composed of lactose, PVP K-30,

and the effervescent base that can be applied by spraying on plant or by direct

broadcasting to water to evaluate its physical and biological characteristics

and to test the efficiency of a novel bacterial formulation in suppressing

sheath blight disease development in greenhouse conditions.

The effect of regular intake of low doses of an effervescent multivitamin

preparation on the free-radical-producing activity of murine peritoneal

macrophages under conditions resembling a possible infection was studied in

vitro. The multivitamin supplementation increased the number, and the

reactive oxygen species-producing activity of macrophages and it lowered the

steady-state free radical concentrations of liver and spleen as measured by

electron paramagnetic resonance spectroscopy(226).

Tartary buckwheat(227), another type of biological effervescent tablets,

mainly contains many kinds of active ingredients such as flavone, which is

showed by the modem research and it can prevent and cure

cerebrocardiovascular disease and diabetes and lower the blood fat.

For the time being, its processing technique is quite poor, producing a very

Results

223

simple and non good dissolubility of the flavone extract.

These effervescent tablets contain both sodium bicarbonate and an organic

acid, which in the water they can create a large amount of carbon dioxide so

as to make the tablet fast to dissolve, nice to taste and easy to carry, making

them especially suitable for children, elder and patients who have difficulty in

swallowing. The main applications were the use in drugs and health-keeping

food.

The TCMCR formulation was successfully prepared with sodium chloride,

sodium hydrogen carbonate and hydroxypropylmethylcellulose (HPMC) as

osmotic agents(228).

Typical drain cleaners can be in liquid or granular form and they contain

sodium hydroxide, sodium nitrate and aluminum.

Sodium hydroxide is usually the largest component in these mixtures, it

generates heat when it is dissolved in water and it reacts with the aluminum,

melting grease, soap, which clog drains. The fats saponification, due to the

generated heat, change the grease into a soap-like substance, which is more

easily rinsed down the drain. Ammonia gas is generated providing agitation

and exposing the clog to fresh sodium hydroxide.

So a typical drain cleaner contains a metal hydroxide (20-60 %), an

hypochlorite generator (20-40 %) and an effervescent system (10-40 %), a

lubrificating agent (1-10 %) and a binding agent (1-10 %)(231,232).

An effervescent method to clean soiled dishes by hand washing was

patented(232). This method of cleaning comprises the addition of an

effervescent product to a volume of water; the contacting volume of water

with the effervescent product and the soiled dishes; their soaking, wiping and

rinsing in contact with the volume of water and the effervescent product for a

period of time.


224

5.1 Conclusions

The foaming agents and the effervescent materials background can be

introduced in a prospective of future trends such as soaps and cleansings

formulations that can be tested and introduced in the industry as proprietary

know how.

The main raw materials used to produce an effervescent system (tablets or

drain cleaners) were sodium carbonate, sodium bicarbonate as basic

component and citric or fumaric acid as acidic component.

Every effervescent product, can contain functional molecules such as

fragrance, essential oils, plant extracts, emollient materials, surfactants as

emulsifiers and foamers, binders and inorganic materials.

The production process consists in two granulates methods that produces a

wet granulation using two separate granulation steps for the alkaline and the

acid components with a subsequent dry blending step. The blend is made in a

high shear granulator, with subsequent drying, a single-pot or in a fluid bed

spray granulator.

Some effervescent products such as tablets based on sugar alcohols or

pearls, organic chlorine solid disinfectant, effervescent additives for calcium

phosphate cements and drain cleaners, are present on the market.

The component concentrations for these latter products have to be

considered an useful tool to do some industrial trials for fabrication of drain

cleaners.

Conclusions

223

CONCLUSIONS

The structural analyses (FT-IR, NMR) conducted on the PHAs samples

obtained from olive oil mills wastewater, confirmed that these materials are

mainly consisting of PHB. The copolymeric nature was detected only for

PAR-7 as shown by the double melting peak in its DSC trace.

TGA traces showed a series of degradation peaks connected with the

components present in the samples. The residue recovered at 500 °C

presented small values for all PAR samples and a drastically decrease for

SAR-4 sample in the SAR series.

GPC experiments led us to know the average molecular weight and the

polydispersion index for all samples. Peaks at higher retention time were

evident in the traces and they were connected to the fermentation and/or the

extraction method.

In regard of the LCA study, this gave a method for a comparative

evaluation of the environmental impact associated to the PHA production

according to the technology developed in POLYVER Project.

For the ligno-cellulosic materials, the percentage of each component was

obtained by chemical analysis. The structural (FT-IR, SEM) and thermal

properties (TGA, DSC) were investigated and led to conclude that the waxes

were responsible for the thermal instability of the materials and that the

acetylation process led to the material less thermally stable materials when

compared to the pristine cellulose.

The thermal characterization of the blends based on PLA and Bionolle

showed that the thermal stability increased with the Bn content, while the

mechanical properties do not play any improvement when Bn content was

superior at a 50 %.

SEM photomicrographs for the CA/PHB blends showed the presence of

two phases with the CA particles dispersed in the PHB matrix.


226

The adhesion between CA and PHB increased with the cellulose acetate

(CA) percentage.

The Tg from DSC experiments was evident only for CA/PHB (50/50)

and CA/PHB (60/40).

WAXD pattern of CA/PHB blends exhibited the main peaks of a semi-

crystalline material and the addition of cellulose acetate (CA) did not

change the crystalline structure of PHB.

Ulva and ground rices dimensional distribution was assessed and it was

found that their granulometry made them suitable for composite

formulations.

TGA analysis gave useful information on the degradation temperature of

all materials that was necessary to know for blending fibers and polymers.

The prepared laminates and composites were investigated for the

structural, morphological, thermal and mechanical properties.

The obtained results for the ulva composites, were an improved adhesion

at the composite interface between the polymer and the filler, a decrease in

thermal stability with the increased filler content and mechanical properties

in agreement with composites which become more fragile by increasing the

algal biomass content.

The addition of an inorganic material improved the density of the

produced items and the TGA analysis confirmed as expected an increase in

the recovered residue amount at 500°C.

The reported background on the foaming agents and effervescent

materials gives useful hints for the production of cleansing and drain

cleaners formulations that are planned to be developed in a forthcoming

doctorate thesis.

References

225

REFERENCES

[1] Takashi F., (1998) ‘Processability and properties of aliphatic

polyesters, BIONOLLE, synthetized by polycondensation reaction’

Polymer Degradation and Stability, 59, 209-214.

[2] Wu C.S., (2003) ‘Physical properties and biodegradability of

maleated-polycaprolactone/starch composite’ Polymer Degradation

and Stability, 80, 127-134.

[3] Yasuniwa M., Iura K., Dan Y. (2007) ‘Melting behaviour of poly(L-

lactic acid): effects of crystallization temperature and time’ Polymer,

48, 5398-5407.

[4] Pillin I., Montrelay N., Grohens Y. (2006) ‘Thermo-mechanical

characterization of plasticized PLA: Is the miscibility the only

significant factor?’ Polymer, 47, 4676-4682.

[5] Scandola M., Focarete M.L., Adamus G., Sikorska W., Baranowska

I., Swierczek S., Gnatowski M., kowalczuk M., Jedlinski Z., (1997)

‘Polymer blends of natural poly(3-hydroxybutyrate-co-3-

hydroxyvalerate) and a synthetic atactic poly(3-hydroxybutyrate).

Characterization and biodegradation studies’ Macromolecules, 30,

2568-2574.

[6] Wu C.S., (2006) ‘Assessing biodegradability and mechanical, thermal

and morphological properties of an acrylic acid-modified poly(3-

hydroxybutyric acid)/wood flours biocomposite’ Journal of Applied

Polymer Science, 102, 3565-3574.

[7] Tomaz Duarte M.A., Hugen R.G., Martins Sant’Anna E., Pezzin

Testa A.P., Pezzin S.H., (2006) ‘Thermal and mechanical behaviour

of injection molded poly (3-hydroxybutyrate)/poly (ε-caprolactone)

blends’ Materials Research, 9, 25-27.


228

[8] Persenaire O., Alexandre M., Degee P., Dubois P., (2001)

‘Mechanism and kinetics of thermal degradation of poly (ε-

caprolactone).’ Biomacromolecules, 2, 288-294.

[9] UNI EN ISO 1183-1, (2005) ‘Methods for determining the density of

non-cellular plastics. Part I: Immersion method, Liquid picnometer

method and titration method.’ Engineering Library, Pisa.

[10] Hocking P.J., (1995) ‘Enzymatic degradability of poly (β-

hydroxybutyrate) as a function of tacticity’, Pure Applied Chemistry

A, 32, 889-894.

[11] Chiellini E., Cinelli P., Imam S.H., Mao L., (2001) ‘Composites films

based on poly(vinylalcohol) and lignocellulosic fibres: preparation

and characterization in biorelated polymers

[12] ASTM Standard E104-02, (2002) "Standard Practice for Maintaining

Constant Relative Humidity by Means of Aqueous Solutions", ASTM

International: West Conshohocken, PA, <www.astm.org>

[13] Cerqueira D.A., Filho G.R., and Meireles C.dS., (2007) ‘Optimization

of sugar cane bagasse cellulose acetylation’, Carbohydrate Polymer,

69, 597-582.

[14] Chiellini E., Cinelli P., Fernandes E.G., Kenawy E.R., and Lazzeri A.,

(2001) ‘Gelatin-Based blends and composites. Morphology and

thermal mechanical characterization’, Biomacromolecules, 2, 806-

811.

[15] Doi Y, Microbial Polyesters, VCH Publishers, New York, (1990).

[16] Byrom D, Plastics from Microbes. Microbial Synthesis of Polymers

and Polymers Precursors, Mobley DP, 5 (1994).

[17] http://inventabrasilnet.t5.com.br/plastico.htm.

[18] Dairy Industry Waste as Source For Sustainable Polymeric Material

Production. ACRONYM: WHEYPOL

Contract n.: G5RD-CT-2001-00591, Project n.: GrD2-2000-30385

References

229

[19] Akita S., Einaga Y., Miyaki Y., Fujita H., (1976) Macromolecules, 9,

774.

[20] Miyaki Y., Einaga Y., Hirosye T., Fujita H., (1977) Macromolecules,

10, 1356.

[21] Csomorova K., Rychly J., Bakos D., Janigova I., (1994) 'The effect of

inorganic additives on the decomposition of poly(beta-

hydroxybutyrate) into volatile products' Polymer Degradation and

Stability, 43, 441-446.

[22] Janigova I., Lacik I., Chodak I., (2002) ‘Thermal degradation of

plasticized poly(3-hydroxybutyrate) investigated by DSC’ Polymer

Degradation and Stability, 77, 35-41.

[23] Azuma Y., Yoshie N., Sakuray M., Inocue Y., Chujo R., (1992)

‘Thermal behaviour and miscibility of

poly(hydroxybutyrate)/poly(vinyl alcohol) blends’ Polymer, 33,

4763-4767.

[24] Sudesh K., Abe H., Doi Y., (2000) ‘Synthesis, structure and

properties of polyhydroxyalkanoates: biological polyesters’ Progress

Polymer Science, 25, 1503-1555.

[25] Day M., Cooney J., Shaw K., Watts J., (1998) ‘Thermal analysis of

some environmentally degradable polymers’ Journal of Thermal

Analysis and Calorimetry, 52(2), 261-274.

[26] Chiellini E., Grillo Fernandes E., Pietrini M., Solaro R., (2003),

Macromol. Symp., 197, 45.

[27] Xie W.P., Chen G., (2008), Biochem. Engin. J., 38, 384.

[28] Luo R., Chen J., Zhang L., Chen G., (2006), Biochem. Engin. J., 32,

218.

[29] Silverstein R. M., Webster F. X.,(1999), ‘Identificazione

Spettroscopica di Composti Organici’, I Ed. Italiana, Casa Editrice

Ambrosiana, Milano.


230

[30] Bayari S., Severcan F., Gursel I., Hasirci V., Alaeddinoglu G.,

(1998),‘The FTIR Studies of the Poly(3-hydroxybutyrate) and

Poly(3hydroxybutyrate-co-3-hydroxyvalerate)’. In: P.I. Harris, and D.

Chapman, New Biomedical Materials, IOS Press, Amsterdam, 58.

[31] Nakanishi K., Solomon P.H., (1977), ‘Infrared Absorption

Spectroscopy’, Holden-Day, Inc., San Francisco.

[32] Xu J., Guo B.H., Yang R., Wu Q., Chen G.Q., Zhang Z.M., (2002),

Polymer, 43, 6893.

[33] Roig A., Cayuela M.L., Sanchez-Monedero M.A., Waste Manag.,

(2006), 26, 960.

[34] Kapellakis I.E., Tsagarakis K.P., Crowther J.C., (2008), Rev. Environ.

Sci. Biotechnol., 7, 1.

[35] CE Directives 271/1991, 676/1991.

[36] Raveendran K., Ganesh A., Khilar K.C., (1996), ‘Pyrolysis

characteristics of biomass and biomass components’, Fuel, Vol.

75(8), 987-998.

[37] Nassar M.M., Ashour E.A., Seddik S.V., (1998), ‘ Thermal

characteristics of bagasse’, Energy Sources, 20,

831-837.

[38] Sun R.C., Sun X.F., Xiao B., (2002), ‘Extraction and characterization

of lyophilise extractives from rice straw. Spectroscopic and thermal

analysis’, Journal of Wood Chemistry and Technology, 22(1), 1-9.

[39] Sun J.X., Sun X.F., Zhao H., Sun R.C., (2004), ‘Isolation and

characterization of cellulose from sugarcane bagasse’, Polymer


[40] Bilba K., Ouensanga A., (1996), ‘Fourier transform infrared

spectroscopic study of thermal degradation of sugar cane bagasse’,

Journal of Analytical and Applied Pyrolysis, 38, 61-73.

[41] Chen Y., (2005).

References

231

[42] Hanna A.A., Basta A.H., El-Saied H., and Abadir I.F., (1999),

“Thermal properties of cellulose acetate and its complexes with some

transition metals”, Polymer Degradation and Stability, 63, 293-296.

[43] Hoareau W., Trindade W.G., Siegmund B., Castellan A., and Frollini

E., (2004), “Sugar cane bagasse and curaua lignins oxidized by

chlorine dioxide and reacted with furfuryl alcohol: characterization

and stability”, Polymer Degradation and Stability, 86, 567-576.

[44] Yang H., Yan R., Chen H., Lee D.H., and Zheng C., (2007),

“Characterstics of hemicellulose, cellulose, and lignin pyrolysis”,

Fuel, 86, 1781-1788.

[45] Sun J.X., Mao F.C., Sun X.F., and Sun R.C., (2004), "Comparative

study of hemicelluloses isolated with alkaline peroxide from

lignocellulosic materials", Journal of Wood Chemistry and

Technology, 24 (3), 239-262.

[46] Cerqueira D.A., Filho G.R., Nascimento de Assuncao R.M., Meireles

C.dS., Toledo L.C., Zeni M., Mello K., and Duarte J., (2008),

“Characterization of cellulose triacetate membranes produced from

sugar cane bagasse, using PEG 600 as additive”, Polymer Bulletin,

60, 397-404.

[47] Ifuku S., Nogi M., Abe K., Handa K., Nakatsubo F., and Yano H.,

(2007), “Surface modification of bacterial cellulose nanofibers for

property enhancement of optically transparent composites:

dependence on acetyl group DS”, Biomacromolecules, 8, 1973-1978.

[48] Samois E., Dart R.K., Dawkins J.V., (1997), "Preparation,

characterization and biodegradation studies on cellulose acetates with

varying degrees of substitution", Polymer, 38(12), 3045-3054.

[49] Hurtubise F.G., (1962), “The analytical and structural aspects of the

infrared spectroscopy of cellulose acetate”, Tappi, 45(6), 460-465.


232

[50] Sun J.X., Sun X.F., Sun R.C., Fowler P., Baird M.S., (2003),

‘Inhomogeneities in the chemical structure of sugar cane bagasse

lignin’, J. Agric. Food Chem, 51, 6719-6725.

[51] Xiao B., Sun X.F., Sun R., (2001), ‘Chemical, structural and thermal

characterizations of alkali-soluble lignins and hemicelluloses, and

cellulose from maize stems, rye straw, and rice straw’, Polymer


[52] Kohler S., Liebert T., Heinze T., (2008), ‘Interactions of ionic liquids

with polysaccharides. Pure cellulose nanoparticles from trimethylsilyl

cellulose synthesized in ionic liquids’, Journal of Polymer Science:

Part A: Polymer Chemistry, 46, 4070-4080.

[53] Shao Z., Li G., Xiong G., Yang W., (2002), ‘Modified cellulose

adsorption method for the synthesis of conducting perovskite powders

for membrane application’, Powder Technology, 122, 26-33.

[54] Cerqueira D.A., Filho G.R., Da Silva Meireles C., (2007),

‘Optimization of sugar cane bagasse cellulose acetylation’,

Carbohydrate Polymers, 69, 579-582.

[55] Cerqueira D.A., Filho G.R., Assuncao R.M..N., (2006), ‘A new value

for the heat of fusion of a perfect crystal of cellulose acetate’,

Polymer Bulletin, 56, 475-484.

[56] Filho G.R., Assuncao R.M.N., Vieira J.G., Meireles CdS., Cerqueira

D.A., Da Silva Barud H., Ribeiro S.J.L., Messaddeq Y., (2007),

‘Characterization of methylcellulose produced from sugar cane

bagasse cellulose: crystallinity and thermal properties’, 92, 205-210.

[57] Auras R.A., Harte B., Selke S., Hernandez R., (2003), ‘Mechanical,

Physical, and Barrier Properties of Poly(lactide) Films’, Journal of

Plastic Film & Sheet, 19(2), 123-135.

[58] Martino V.P., Ruseckaite R.A., Jimenez A., ‘Processing and

Mechanical Characterization of Plasticized Poly(lactide acid) Films

References

233

for Food Packaging’, Proceeding of the 8th Polymers for Advanced

Technologies International Symposium, Budapest, Hungary, 13-16

Settembre 2005.

[59] Inglis T.L., “An Improved Packaging Film from Polylactic Acid”,

Can. Pat. Appl. 2005 CA 2472420, 19pp.

[60] Auras R.A., Harte B., Selke S., (2004), ‘An overview of Polylactides

as Packaging Materials’, Macromolecular Bioscience, 4(9), 835-864.

[61] Auras RA, Singh SP, Singh JJ, (2005), ‘Evaluation of Oriented

Poly(lactide) Polymers vs. Existing PET and Oriented PS for Fresh

Food Service Containers’, Packaging Technology & Science, 18(4),

207-216.

[62] Holm V.K., Ndoni S., Risbo J., (2006), ‘The Stability of Poly(lactic

acid) Packaging Films as Influenced by Humidity and Temperature’,

Journal of Food Science, 71(2), E40-E44.

[63] Inomata I., (2005), ‘Green Plastics with Advancing Reform. 1. The

Prospects and the Theme of the Plant-Based Film Ecology’,

Mitsubishi Plastics, Inc., 34(11), 30-32.

[64] Lagaron J.M., Cabedo L., Cava D., Feijoo J.L., Gavara R., Gimenez

E., (2005), ‘Improving Packaged Food Quality and Safety. Part 2:

Nanocomposites’, 22(10), 994-998.

[65] Lim K., Mustapha A., (2003), ‘Reduction of Escherichia Coli

O157:H7 and Lactobacillus Plantarum Numbers on Fresh Beef by

Polylactic Acid and Vacuum Packaging’, Journal of Food Science,

68(4), 1422-1427.

[66] Jacobsen S., Fritz H.G., Degee P., Dubois P., Jerome R., (2000),

‘New Developments on the Ring Opening Polymerization of

Polylactide’, Industrial Crops and Products, 11(2-3), 265-275.

[67] Aritake T., “Polylactic Acid Resin Compositions for Thermoforming,

Polylactic Acid Resin Sheets for Thermoforming, and Thermoformed


234

Objects Obtained Therefrom”, PCT Int. Appl. 2004 WO 2003-

JP16642, 23 pp.

[68] Johnson M., Shivkumar S., Berlowitz-Tarrant L., (1996), ‘Structure

and properties of filamentous green algae’, Materials Science and

Engineering B, 38, 103-108.

[69] Taddei P., Tinti A., Reggiani M., Fagnano C., (2005), ‘In vitro

mineralization of bioresorbable poly(ε-caprolactone)/apatite

composites for bone tissue engineering: a vibrational and thermal

investigation’, Journal of Molecular Structure, 744-747, 135-143.

[70] Ali R., Iannace S., Nicolais L., (2003), ‘Effects of processing

conditions on the impregnation of glass fibre mat in

extrusion/calendering and film stacking operations’, Composites

Science and Technology, 63, 2217-2222.

[71] Wu C.S., (2003), ‘Physical properties and biodegradability of

maleated-polycaprolactone/starch composite’, Polymer Degradation

and Stability, 80, 127-134.

[72] Wu C.S, (2006), J. Appl. Polym. Sci., 102, 3565–3574.

[73] Otey, F.H.; Mark, A.M.; Mehltretter C.L.; Russell, C.R. (1974) Ind.

Eng. Chem. Res., 13, 90-92.

[74] Lahalih, S.M.; Akashah, S.A.; Al-Hajjar, F.H., (1987), Ind. Eng.

Chem. Res., 26, 2366-2372.

[75] Coffin, R.; Fishman, M.L.; Ly, T.V. (1996), J. Appl. Polym. Sci., 57,

71-79.

[76] Chen, L.; Imam, S.H.; Gordon, S.H.; Greene, R.V., (1997), J.

EnViron. Polym. Degrad., 5, 111-117.

[77] Chiellini E., Cinelli P., Corti A., Kenawy E. R., Grillo- Fernandes E.,

Solaro R., (2000), Macromol. Symp. 152, 83-94.

[78] Mao L., Imam S.H., Gordon S., Cinelli P., Chiellini E., (2000), J.

Polymers & Environment, 8, 205.

References

235

[79] Chiellini E., Cinelli P., Imam S.H., Mao L., (2001),

Biomacromolecules, 2, 1029.

[80] Chiellini E., Cinelli P., Grillo Fernandes E., Kenawy E.R., Lazzeri A.,

(2001), Biomacromolecules, 2, 806.

[81] Cinelli P., Chiellini E., Lawton J.L., Imam S.H., (2006), J. Polymer

Research 13, 107-114

[82] Chiellini E., Cinelli P., Ilieva V.I., (2008), Int. J. Materials and

Product Technology, 10(10)…

[83] Paradossi G., Cavalieri F., Pizzoferrato L., Liquori A. M., (1999), Int

.J. Biol. Macromol., 25, 309-315.

[84] Scandola M., Focarete M. L., Adamus G., Sikorska W., Baranowska

I., Sa Wierczek S., Gnatowski M., Kowalczuk M., Ski Z. J., (1997)

Macromolecules, 30, 2568-2574.

[85] Averous L., Moro L., Dole P., Fringant C., (2000), ‘Properties of

thermoplastic blends: starch-polycaprolactone’, Polymer 41, 4157–

4167.

[86] Duarte M. A. T, Hugen R. G., Martins E.S., Pezzin A. P. T., Pezzin S.

H., (2006), Materials Research, 9(1), 25-27.

[87] Mitchell C.A., Krishnamoorti R., (2005), ‘Non-isothermal

crystallization of in situ polymerized poly(ε-caprolactone)

functionalized-SWNT nanocomposites’, Polymer, 46, 8796-8804.

[88] Singh R.P., Pandey J.K., Rutout D., Degee Ph., Dubois Ph., (2003),

‘Biodegradation of poly(ε-caprolactone)/starch blends and composites

in composting and culture environments: the effect of

compatibilization on the inherent biodegradability of the host

polymer’, Carbohydrate Research, 338, 1759-1769.

[89] Lepoittevin B., Devalckenaere M., Pantoustier N., Alexandre M.,

Kubies D., Calberg R., Jerome R., Dubois P., (2002), ‘Poly(ε-

caprolactone)/clay nanocomposites prepared by melt intercalation:


236

mechanical, thermal and rheological properties’, Polymer, 43, 4017-

4023.

[90] Sorrentino A., Gorrasi G., Tortora M., Vittoria V., Costantino U.,

Marmottini F., Padella F., (2005), ‘Incorporation of Mg-Al

hydrotalcite into a biodegradable poly(ε-caprolactone) by high energy

ball milling’, Polymer, 46, 1601-1608.

[91] Chen B., Sun K., (2005), ‘Poly(ε-caprolactone)/hydroxyapatite

composites: effects of particle size, molecular weight distribution and

irradiation on interfacial interaction and properties’, Polymer Testing,

24, 64-70.

[92] Wu C.S., (2005), ‘A comparison of the structure, thermal properties,

and biodegradability of polycaprolactone/chitosan and acrylic acid

grafted polycaprolactone/chitosan’, Polymer, 46, 147-155.

[93] Singh S., Mohanty A.K., (2007), ‘Wood fiber reinforced bacterial

bioplastic composites: Fabrication and performance evaluation’,

Composites Science and Technology, 1753-1763.

[94] Wu C.S., (2006), ‘Assessing biodegradability and mechanical,

thermal, and morphological properties of an acrylic acid-modified

poly(3-hydroxybutyric acid)/wood flours biocomposite’, Journal of

Applied Polymer Science, 102, 3565-3574.

[95] POLYVER Project

[96] Abayasinghe M, Suresh S, Perera P, Smith D., (2003), ‘Synthesis and

Characterization of Poly(ester amide)s Derived from Lactide and

Depsipeptides’, 55th Southeast Regional Meeting of the American

Chemical Society, Atlanta, GA, United States, Washington.

[97] Aritake T, (2004), “Polylactic Acid Resin Compositions for

Thermoforming, Polylactic Acid Resin Sheets for Thermoforming,

and Thermoformed Objects Obtained Therefrom”, PCT Int. Appl.

2004 WO 2003-JP16642, 23 pp.

References

237

[98] Auras R.A, Singh S.P, Singh J.J, (2005), “Evaluation of Oriented

Poly(lactide) Polymers vs. Existing PET and Oriented PS for Fresh

Food Service Containers”, Packaging Technology & Science, 18(4),

207-216.

[99] Auras R.A, Harte B, Selke S, (2004), “An overview of Polylactides as

Packaging Materials”, Macromolecular Bioscience, 4(9), 835-864.

[100] Auras R.A, Harte B, Selke S, Hernandez R, (2003), “Mechanical,

Physical, and Barrier Properties of Poly(lactide) Films”, Journal of

Plastic Film & Sheet, 19(2), 123-135.

[101] Avella M, De Vlieger J.J, Errico M.E, Fisher S, Vacca P, Volpe M.G,

(2005), “Biodagradable Starch/Clay Nanocomposites Films for Food

Packaging Applications”, Food Chemistry, 3, 467-474.

[102] Bassam E. N, (2001), Renewable Energy for Rural Communities,

Renewable Energy, 24, 40.

[103] Bastioli C, Milizia T, Floridi G, Scaffidi Lallaro A, Cella G. D, Toisin

M, “Biodegradable Aliphatic-Aromatic Polyesters Mostly on Azelaic

acid, their Blends with other Biodegradable Polymers, and Uses”,

PCT Int. Appl. 2006 WO 2006-EP2673, 29pp.

[104] Sperling L. H, Carraher C. E, Polymers from Renewable resources in

H. F Mark, N. M Bikales, C. G Overberger, G. Menges (eds.)

Encyclopedia of Polymer Science and Engineering, Wiley, New

York, 1988, 12, 658-690.

[105] Bozel J. J ed, Chemicals and Materials from Renewable Resources,

Proceedings of a Symposium held at the 218th National Meeting of

the ACS in New Orleans, Louisiana, 22-26 August 1999, ACS Symp.

Ser. 784, ACS, Washington D. C, USA, 226pp, 2001.

[106] Yu L, Dean K, Li L (2006), “Polymer Blends and Composites from

Renewable Resources”, Progress Polymer Science, 31, 576-602.


238

[107] Mareschal F, Biodegradable Plastics Views of APME (Association of

Plastics Manufacturers in Europe) in E. Chiellini, R. Solaro eds.

Biodegradable Polymers and Plastics, Kluwer Academic/Plenum

Publishers NY, pp.67-71, 2003.

[108] Warwel S, Bruse F, Demes C, Kunz M, Klaas M.R (2001), “Polymers

and Surfactants on the Basis of Renewable Resources “Chemosphere,

43, 39-48.

[109] Roper H, Renewable Raw Materials in Europe- Industrial Utilization

of Starch and Sugar, NutraCos, May-June (2002), 37-44.

[110] Petersen K, Nielsen P.V, Olsen M.B (2001), ”Physical and

Mechanical Properties of Biobased Materials-Starch, Polylactate and

Polyhydroxybutyrate”, Starch/Staerke, 53(8), 356-361.

[111] Pillin I, Montrelay N, Grohens Y (2006), “Thermo-Mechanical

Characterization of Plasticized PLA: Is the Miscibility the Only

Significant Factor?”, Polymer, 47(13), 4676-4682.

[112] Martino V.P, Ruseckaite R.A, Jimenez A, “Processing and

Mechanical Characterization of Plasticized Poly(lactide acid) Films

for Food Packaging”, Proceeding of the 8th Polymers for Advanced

Technologies International Symposium, Budapest, Hungary, 13-16

Settembre 2005.

[113] Cargill Dow LLC, Can. (2004), “That’s wrap! Corn Yields a Natural

Solution for Suistanable Food Packaging”, Canadian Chemical News,

56(1), 16-17.

[114] Holm V.K, Ndoni S, Risbo J (2006a), “The Stability of Poly(lactic

acid) Packaging Films as Influenced by Humidity and Temperature”,

Journal of Food Science, 71(2), E40-E44.

[115] Lagaron J.M, Cabedo L, Cava D, Feijoo J.L, Gavara R, Gimenez E

(2005), “Improving Packaged Food Quality and Safety. Part 2:

Nanocomposites”, 22(10), 994-998.

References

239

[116] Lim K, Mustapha A (2003), “Reduction of Escherichia Coli O157:H7

and Lactobacillus Plantarum Numbers on Fresh Beef by Polylactic

Acid and Vacuum Packaging”, Journal of Food Science, 68(4), 1422-

1427.

[117] Jacobsen S, Fritz H.G, Degee P, Dubois P, Jerome R (2000), “New

Developments on the Ring Opening Polymerization of Polylactide”,

Industrial Crops and Products, 11(2-3), 265-275.

[118] Fang J.M, Fowler P.A, Escrig C, Gonzalez R, Costa J.A, Chamudius

L (2005), “Development of Biodegradable Laminate Films Derived

from Naturally Occurring Carbohydrate Polymers”, Carbohydrate

Polymers, 60(1), 39-42.

[119] Cabedo L, Feijoo J.L, Villanueva M.P, Lagaron J.M, Gimenez E

(2006), “Optimization of Biodegradable Nanocomposites Based on

PLA/PCL Blends for Food Packaging Applications”,

Macromolecular Symposia, 233, 191-197.

[120] Choi W.Y, Lee C.M (2006), “Development of Biodegradable Hot-

Melt Adhesive Based on Poly-ε-Caprolactone and Soy Protein Isolate

for Food Packaging System”, LWT- Food Science and Technology”,

39(6), 591-597.

[121] Haugaard V.K, Danielsen B, Bertelsen G (2003), “Impact of

Polylactate and Poly(hydroxybutyrate) on Food Quality”, European

Food Research and Technology, 216(3), 233-240.

[122] Rhim J.W, Mohanty K.A, Singh S.P, Ng, Perry K.W (2006),

“Preparation and Properties of Biodegradable Multilayer Films Based

on Soy Protein Isolate and Poly(lactide)”, Industrial & Engineering

Chemistry Research, 45(9), 3059-3066.

[123] Yamane K, Kawakami Y, Hokari Y, “Biodegradable Multilayered

Polyglycolic Acid Resin Sheet”, PCT Int. Appl. 2006 WO 2003-

JP6704, 22pp.


240

[124] Wang T, “Biodegradable Laminate Materials Containing Poly(lactic

acid) and Polyvinyl Alcohol Outer Layers for Packaging Liquid Food

and their Manufacture”, 2002 CN 1359790, 6pp.

[125] Sato T, Yamane K, Wakabayashi J, Sato Tomoaki, Suzuki T,

“Multilayer Sheet Made of Polyglycolic acid Resin”, PCT Int. Appl.

2006 WO 2005-JP11261, 18pp.

[126] Cleveland C.S, Reighard T.S, “Biodegradable Paper-Based Cup or

Package and Production Method”, U.S. Pat. Appl. Publ.2006 US

2005-221175, 7pp.

[127] Bonutti P.M, “Biodegradable Packaging Materials”, U. S. Pat. Appl.,

Publ. 2005 US 2005-123497, 15pp.

[128] Matsunaga A, Chikamasa N, Yoshida N, “Polylactic Acid-Based

Long-Fiber Nonwoven Fabrics, Biodegradable Bags Containing the

Same, and Manufacture Thereof”, Jpn. Kokai Tokkyo koho 2006 JP

2005-232682, 21 pp.

[129] Sebastien F, Stephane G, Copinet A, Coma V (2006), “Novel

Biodegradable Films Made from Chitosan and Poly(lactic acid) with

Antifungal Properties Against Mycotoxinogen Strains”,

Carbohydrate Polymers, 65(2), 185-193.

[130] Nakamura T, Iwazaki K, Kato M, Maruyama I, ”Biodegradable

Polylactic Acid Multylayer Film and Formation Process thereof”,

PCT Int. Appl. 2004 WO 2004-JP1236, 17pp.

[131] Wang T, “Composite Material for Packaging Food and its Production

Process”, 2001 CN 99-125782, 5pp.

[132] Li L, Kerry J.F, Kerry J.P (2005), ”Selection of Optimum Extrusion

Technology Parameters in the Manufacture of Edible/Biodegradable

Packaging Films Derived from Food-Based Polymers”, J. of Food,

Agricolture & Environment, 3(3-4), 51-58.

[133] Wang L, Shogren R, Carriere C (2000), “Preparation and Properties

References

241

of Thermoplastic Starch-Polyester Laminate Sheets by Coextrusion”,

Polymer Engineering and Science, 40(2), 499-506.

[134] Steinka I, Morawska M, Rutkowska M, Kukulowicz A (2006), “The

Influence of Biological Factors on Properties of Some Traditional and

New Polymers Used for Fermented Food Packaging”, Journal of

Food Engineering, 77, 771-775.

[135] Mori H, Iwasaki Y, Kobayashi Y, “Biodagradable Bags for

Packaging Foods Available in High-Speed Production”, PCT Int.

Appl. 2002 WO 2002-JP858, 37pp.

[136] Oksman K, Skrifvars M, Selin J. F (2003), “Natural fibres as

reinforcement in polylactic acid (PLA) composites”, Composites

Science and Technology, 63, 1317-1324.

[137] Balan V., Sousa L. C., Chundawat S. P. S., Vismeh R., Jones A. D.,

and Dale B.E. (2008), "Mushroom spent straw: a potential substrate

for an ethanol-based biorefinery", J Ind Microbiol Biotechnol, 35,

293–301.

[138] Chen T., Breuil C., Carriere S., and Hatton J.V. (1994), Tappi J., 77,

235.

[139] Doherty W., Halley P., Edye L., Rogers D., Cardona F., Park Y., and

Woo T. (2007), "Studies on polymers and composites from lignin and

fiber derived from sugar cane", Polym. Adv. Technol., 18, 673-678.

[140] Gong R., Jin Y., Chen J., Hu Y., and Sun J. (2007), "Removal of

basic dyes from aqueous solution by sorption on phosphoric acid

modified rice straw", Dyes and Pigments, 73, 332-337.

[141] Habibi Y., El-Zawawy W. K., Ibrahim M. M., Dufresne A. (2008),

"Processing and characterization of reinforced polyethylene

composites made with lignocellulosic fibers from Egyptian agro-

industrial residues", Composites Science and Technology, 68, 1877–

1885.


242

[142] Barkalow D. G., Rowell R. M., and Young R. A. (1989), "A new

approach for the production of cellulose acetate: acetylation of

mechanical pulp with subsequent isolation of cellulose acetate by

differential solubility", Journal of Applied Polymer Science, 37, 1009-

1018.

[143] Chen G.Q., Wu Q., Zhao K., Yu H.P., and Chan A. (2000), Chin J.

Polym. Sci., 18, 389.

[144] Edgar K. J., Buchanan C. M., Debenham J. S., Rundquist P. A., Seiler

B. D., and Shelton M. C. (2001), "Advances in cellulose ester

performance and application", Progress in Polymer Science, 26,

1605-1688.

[145] Gamez S., Gonzalez-Cabriales J. J., Ramirez J. A., Garrote G., and

Vazquez M. (2006), J. Food Eng., 74, 78.

[146] Greco P., and Martuscelli E. (1989), Polymer, 30, 1475.

[147] Inoue Y., and Yoshie N. (1992), Prog. Polym. Sci., 17, 571.

[148] Liu C.F., Sun R.C., Zhang A.P., and Ren J.L. (2007), Carbohydrate

Polymer, 68, 17.

[149] Luo R., Xu K., and Chen G.-Q. (2007), "Study of miscibility,

crystallization, mechanical properties, and thermal stability of blends

of poly(3-hydroxy butyrate) and poly(3-hydroxy butyrate-co-4-

hydroxy butyrate)", Journal of Applied Polymer Science, 105, 3402-

3408.

[150] Meireles C.dS., Filho G.R., and Nascimento de Assuncao R.M.

(2007), Journal of Applied Polymer Science, 104, 909.

[151] Reverley A. (1985), in Cellulose and its Derivatives. Ed. J.F.

Kennedy. Ellis Horwood, Chichester, Ch. 17, p. 211.

[152] Rodringues J. A. F. R., Parra D. F., and Lugao A. B. (2005), J.

Therm. Anal. Cal., 79, 379.

References

243

[153] Sarrouh B. F., Silva S. S., Santos D. T., and Converti A. (2007),

Chem. Eng. Technol., 30, 270.

[154] Steinmeier H. (2004), "Acetate manufacturing, process, and

technology", Macromolecular Symposia, 208, 49-60.

[155] Yang H., Li Z.S., Lu Z.Y., and Sun C.C. (2005), Eur. Polym. J., 41,

2956.

[156] Xu S., Luo R., Wu L., Xu K., Chen G.-Q. (2006), "Blending and

characterizations of microbial poly(3-hydroxybutyrate) with

dendrimers", Journal of Applied Polymer Science, 102(4), 3782-3790.

[157] Das P., Ganesh A,. and Wangikar P. (2004), Biomass and Bioenergy,

27, 445-457.

[158] Philip S., Keshavarz T., Roy I (2007), “Polyhydroxyalkanoates:

biodegradable polymers with a range of applications”, Journal of

Chemical Technology and Biotechnology, 82, 233-247.

[159] Turning a Liability into an Asset: Landfill Methane Utilisation

Potential in India, August 2008.

[160] LeVan S. L (1989), In: Schniewind, Arno P., ed. Concise

Encyclopedia of Wood & Wood –Based Materials. Ist edition.

Elmsford, NY: Pergamon Press: 271-273

[161] Alvarez V.A, Vazquez A (2004), “Thermal degradation of cellulose

derivatives/starch blends and sisal fibre biocomposites”, Polymer


[162] Sun J.X, Sun X.F, Sun R.C, Su Y.Q (2004), “Fractional extraction

and structural characterization of sugarcane bagasse hemicelluloses”,

Carbohydrate Polymers, 56, 195-204.

[163] Angelidaki I., Ellegaard L., Kioer Ahring B. (2003), “Applications of

the Anaerobic Digestion Process’’, Advances in Biochemical

Engineering/Biotechnology, 82, 1-33.


244

[164] Briassoulis D. (2004), ‘’An Overview on the Mechanical Behaviour

of Biodegradable Agricultural Films’’, Journal of Polymers and the

Environment, 12, 65-81.

[165] Narayan R., www.msu.edu/user/narayan.

[166] Functional Material Solutions 2007, 2008, 2009, 2010. Editor: Jari

Koskinen, Graphic Design: Tuija Soininen, Copyright: VTT

Technical Research Centre of Finland 2008.

[167] Grima S., Bellon-Maurel V., Feuilloley P., Silvestre F. (2002),

‘’Aerobic Biodegradation of Polymers in Solid-State Conditions: A

Review of Environmental and Physicochemical Parameter Settings in

Laboratory Simulations’’, Journal of Polymers and the Environment,

8(4), 183-195.

[168] Gopinathan M. C., Sudhakaran R. (2009), ’’Biofuels: opportunities

and challenges in India’’, In Vitro Cell. Dev. Biol.-Plan, 45, 350-371.

[169] Rutz D.; Janseen R. Biofuel technology handbook. WIP Renewable

Energies, Munich 2007.

[170] FAO (Food and Agriculture Organization) The state of food and

agriculture 2008: Biofuels: Prospects, risks and opportunities.

FAO, Rome2008.

[171] Martinot E. Renewables 2007—global status report.

[172] Dufey, A. (2006),’’Biofuels production, trade and sustainable

development: Emerging issues’’, Sustainable Markets Discussion

Paper No. 2.

[173] Koplow D. (2007), ’’Biofuels—at what cost? Government support for

ethanol and bio-diesel in the United States: 2007 update’’. Global

subsidies initiative of the International Institute for Sustainable

Development.

[174] Kutas G.; Lindberg C.; Steenblik R. (2007), ‘’Biofuels—at what cost?

Government support for ethanol and bio-diesel in the European

References

245

Union: 2007 update’’. Global subsidies initiative of the International

Institute for Sustainable Development.

[175] Steenblik R. (2007), ’’Biofuels—at what cost? Government support

for ethanol and bio-diesel in selected OECD countries: 2007 update’’.

[176] Bailey, R. (2008), ‘’Another inconvenient truth’’. Oxfam briefing

paper. http://www.oxfam.org/pressroom/press release/2008-06-

25/another-inconvenient-truth-biofuels-are-notanswer.

[177] IEA (International Energy Agency) World energy outlook 2007:

China and India insights. OECD/IEA, Paris; 2007b. http://www.

iea.org/textbase/npsum/WEO2007SUM.pdf.

[178] Worldwatch Institute Biofuels for transportation: Global potential and

implications for sustainable agriculture and energy in the 21st century.

Worldwatch Institute, Washington, DC; 2007.

http://www.worldwatch.org/node/4078.

[179] Mitchell, D. (2008), ‘’A note on rising food prices. Policy research

working paper, 4682’’. The World Bank, Development Prospects

Group; 2008.

http://www wds.worldbank.org/external/default/WDSContentServer/

WDSP/IB/2008/07/28/000020439_20080728103002/Rendered/

PDF/WP4682.pdf.

[180] Searchinger T.; Heimlich R.; Houghton R. H.; Dong F.; Elobeid A.;

Fabiosa J.; Togkoz S.; Hayes D.; Yu T. (2008), ‘’Use of US croplands

for biofuels increases greenhouse gases through emissions from land

use change’’. Science, 319, 1238–1240.

[181] World Bank Rising food prices: Policy options and World Bank

response. World Bank, New York; 2008

http://siteresources.worldbank.org/

NEWS/Resources/risingfoodprices_backgroundnote_apr08.pdf.


246

[182] Dufey A.; Vermeulen S.; Vorley B. (2007), ‘’Biofuels: Strategic

choices for commodity dependent developing countries’’. Common

Fund for Commodities, Amsterdam2007.

[183] Banse M.; Nowicki P.; Van Meijl H. (2008), ‘’Why are current food

prices so high. In: Zuurbier P.; Van de Vooren J. (eds) Sugarcane

ethanol: Contributions to climate change mitigation and the

environment. Wageningen Academic, Wageningen, pp 227–248.

http://library.wur.nl/way/bestanden/clc/1880664.pdf.

[184] DEFRA (Department for Environment, food and Rural Affairs) A

sustainability analysis of the Brazilian Ethanol, UNICAMP

www.unica.com.br/download.asp?mmdCode=1A3D48D9-99E6-

4B81-A863-5B9837E9FE39; 2008.

[185] UNICA Sugarcane in Brazil sustainable energy and climate. UNICA,

São Paulo; 2008a. http://english.unica.com.br/multimedia. UNICA

Brazilian sugarcane ethanol: Get the facts rights and kill the myths.

UNICA, São Paulo; 2008b. http://www.unica.com.br/download.asp.

[186] IEA (International Energy Agency) Renewables in global energy

supply: An IEA fact sheet. OECD/IEA, Paris; 2007a. Available at:

http://iea.org/textbase/papers/2006/renewable_factsheet.pdf.

[187] Swain S. N., Biswal S. M., Nanda P. K., Nayak P. L. (2004),

‘’Biodegradable Soy-Based Plastics: Opportunities and Challenges’’,

Journal of Polymers and the Environment, 12(1), 35-42.

[188] Philip S., Keshavarz T., Roy I. (2007), ‘’Polyhydroxyalkanoates:

biodegradable polymers with a range of applications’’, Journal of

Chemical Technology and Biotechnology, 82, 233-247.

[189] Wang Y.Z., Yang K.K., Wang X.L., Zhou Q., Zheng C.Y., Chen Z.F.

(2004), ‘’Agricultural Application and Environmental Degradation of

Photo-Biodegradable Polyethylene Mulching Films’’, Journal of

Polymers and the Environment, 12(1), 7-10.

References

247

[190] Plastics Additives & Compounding September/October 2006, pp. 22-

25.

[191] Ahmad M. (2004), ‘’Thermoplastic micro-spheres as foaming agents

for wood plastic composites’’, WPC 2004 Conference, Vienna,

Austria.

[192] Plastics Additives & Compounding May 2002, pp.24-26.

www.epieurope.com/en/chemical-foaming-agents.php

[193] www.colormatrix.com/en/products/foaming-agents.html

[194] ‘’Protein foaming agent GreenFroth for light weight cellular concrete

for foamed concrete’’, www.greenfroth.com/index.php

[195] US Patent 5643510-‘’Producing foamed gypsum board using a

foaming agent blend’’,

[196] www.patentstorm.us/patents/5643510/fulltext.html

[197] http://njzhulijiang.en.made-in-china.com/product/ybOnJmdxVG

[198] www.westsenior.co.uk/additiveBlends.aspx

[199] ‘’OnCap Chemical Foaming Agents’’, www.polyone.com

[200] Foaming Agents by Alqemia Group

[201] ‘’MILLIFOAM: Gypsum Foaming Agents’’, www.huntsman.com

[202] AQF-2TM Foaming Agent

[203] http//old.finintertrade.ru/en/materials/foaming/

[204] Choy et al., US Patent 4548649

[205] www.dr-luca.de/web/en/foaming_agent/

[206] www.lioncopolymer.com/prods_foamers.html

[207] ‘’Effervescent Technology Primer’’.

[208] Lee R. E., ‘’Effervescent Tablets: Key Facts about Unique, Effective

Dosage Form’’, Amerilab Technologies.

[209] www.pharmpedia.com

[210] www.pharmpedia.com

[211] www.gea-ps.com/npsportal/cmsdoc.nsf/WebDoc/ndkw74tg54


248

[212,213] Smith M. W., ‘’Utilization of Effervescent Spray Technology

to Eliminate Volatile and toxic Diluents’’, Science &

Engineering: Adhesive Materials & Processes, pp.5-10.

[214] ‘’Pearl Calcium Effervescent Tablets’’,

www.tootoo.com/d-rp11897375-Pearl_Calcium_Effervescent

[215] ‘’LiFizz- Effervescent Calcium Plus D-Strawberry Flavored’’

www.zooscape.com/cgi-bin/maitred/GreenCanyon/questp4

[216] ‘’Tubes make effervescent energy tablets portable for consumers’’,

(2008),

www.healthcare-packaging.com/archives/2008/01/tubes_m

[217] Zhang P., Li G.C., Zhang H.P., Yang L.C., Wu Y.P. (2009),

‚’Preparation of porous polymer electrolyte by a microwave assisted

effervescent disintegrable reaction’’, Electrochemistry

Communications, 11, 161-164.

[218] ‘’Effervescent Plastics Promise More With Less’’

http://blog.ecolect.net/2008/11/effervescent-plastics-promise-more

[219] ‘’Look for cooperation on erythritol effervescent tablets’’

www.1biw.com/pj_view.aspx?id=6987

[220] ‘’Effervescent Chlorine Disinfectant Tablet’’

www.made-in-china.com/china-products/productviewOiJn

[221] ‘’Investigation of an effervescent additive as porogenic agent for bone

cement macroporosity’’

www.find-health-articles.com/rec_pub_17264385-investigation

[222] ‘’Effervescent Dosage Manufacturing’’

http://pharmtech.findpharma.com/pharmtech/Analytical/Effervescent

[223] ‘’Effervescent Creatine vs. Creatine Monohydrate’’

www.illpumpyouup.com/articles/effervescent-creatine-vs-cre

[224] ‘’The value range’’, www.oystar.manesty.com

[225] Wiwattanapatapee R., Chumthong A., Pengnoo A.,

References

249

Kanjanamaneesathian M., (2007), ‘’Effervescent fast-disintegrating

bacterial formulation for biological control of rice sheath blight’’,

Journal of Controlled Release, 119, 229-235.

[226] Jakus J., Kriska T., Vanyur R., (2002), ’’Effect of multivitamins in an

effervescent preparation on the respiratory burst of peritoneal

macrophages in mice’’, British Journal of Nutrition, 87, 501-508.

[227] Liang Z., Jingdong Y., Yibing H., Gang Z., (2004), ‘’Technological

Research on Bioflavonoid Effervescent Tablet of Tartary

Buckwheat’’, Section F: Nutrition and Pharmacy, pp.563-566.

[228] Li X. D., Pan W. S., Nie S. F., Wu L. J., (2004)‚’Studies on

controlled release effervescent osmotic pump tablets from Traditional

Chinese Medicine Compound Recipe’’, Journal of Controlled

Release, 96, 359-367.

[229] (WO/2004/020570) ‘’Effervescent Hot Tablet’’,

www.wipo.int/pctdb/en/wo.jsp?WO=20044020570&IA=WO

[230] US Patent Office 2,999,293, patented Sept. 12, 1961

[231] (WO/2000/040688) ‘’Drain Cleaner’’,

www.wipo.int/pctdb/en/wo.jsp?wo=2000040688&IA=US2

[232] ‘’Use of an effervescent product to clean soiled dishes by hand

washing’’

www.freshpatent.com/Use-of-an-effervescent-product-to-cl

[233] Akiyama M., Tsuge T., Y. Doi Y., (2003), ‘Environmental life cycle

comparison of polyhydroxyalkanoates produced from renewable

carbon resources by bacterial fermentation’, Polym. Degrad. Stab.,

80, 183.

[234] Harding K. G., Dennis J. S., Blottnitz H., Harrison S. T. L, (2007), J.

Biotechnol., 130, 57.

[235] Harrison S.T.L., ‘The Extraction and Purification of Alicaligens

Eutrophus, PhD Dissertation, Cambridge University (1990).


250

[236] Petkovica G., Engelsen C. J., Haoyad A. O., Breedveld G., (2004),

‘Environmental impact from the use of recycled materials in road

construction: a method for decision making in Norway’, Resources,

Conservation and Recycling, 42, 249-264.

[237] Kim J., Yun S., Ounaies Z., (2006), ’Discovery of cellulose as a smart

material’, Macromolecules, 39, 4202-4206.

[238] La Scala J., Wool R. P., (2005), ‘Property analysis of triglyceride-

based thermosets’, Polymer, 46, 61–69.

[239] Bansil R, Hermann HJ, Stauffer D., (1984), Macromolecules, 17,

998–1004.

[240] Sahimi M, Arbabi S., (1993), Phys Rev B;47:703–12.

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